1 /*
   2  * Copyright (c) 1996, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 /*
  27  * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
  28  * (C) Copyright IBM Corp. 1996 - 1999 - All Rights Reserved
  29  *
  30  * The original version of this source code and documentation
  31  * is copyrighted and owned by Taligent, Inc., a wholly-owned
  32  * subsidiary of IBM. These materials are provided under terms
  33  * of a License Agreement between Taligent and Sun. This technology
  34  * is protected by multiple US and International patents.
  35  *
  36  * This notice and attribution to Taligent may not be removed.
  37  * Taligent is a registered trademark of Taligent, Inc.
  38  *
  39  */
  40 
  41 package java.util;
  42 
  43 import java.io.IOException;
  44 import java.io.InputStream;
  45 import java.io.UncheckedIOException;
  46 import java.lang.ref.Reference;
  47 import java.lang.ref.ReferenceQueue;
  48 import java.lang.ref.SoftReference;
  49 import java.lang.ref.WeakReference;
  50 import java.lang.reflect.Constructor;
  51 import java.lang.reflect.InvocationTargetException;
  52 import java.lang.reflect.Modifier;
  53 import java.net.JarURLConnection;
  54 import java.net.URL;
  55 import java.net.URLConnection;
  56 import java.security.AccessController;
  57 import java.security.PrivilegedAction;
  58 import java.security.PrivilegedActionException;
  59 import java.security.PrivilegedExceptionAction;
  60 import java.util.concurrent.ConcurrentHashMap;
  61 import java.util.concurrent.ConcurrentMap;
  62 import java.util.jar.JarEntry;
  63 import java.util.spi.ResourceBundleControlProvider;
  64 import java.util.spi.ResourceBundleProvider;
  65 import java.util.stream.Collectors;
  66 import java.util.stream.Stream;
  67 
  68 import jdk.internal.loader.BootLoader;
  69 import jdk.internal.misc.JavaUtilResourceBundleAccess;
  70 import jdk.internal.misc.SharedSecrets;
  71 import jdk.internal.reflect.CallerSensitive;
  72 import jdk.internal.reflect.Reflection;
  73 import sun.security.action.GetPropertyAction;
  74 import sun.util.locale.BaseLocale;
  75 import sun.util.locale.LocaleObjectCache;
  76 import static sun.security.util.SecurityConstants.GET_CLASSLOADER_PERMISSION;
  77 
  78 
  79 /**
  80  *
  81  * Resource bundles contain locale-specific objects.  When your program needs a
  82  * locale-specific resource, a <code>String</code> for example, your program can
  83  * load it from the resource bundle that is appropriate for the current user's
  84  * locale. In this way, you can write program code that is largely independent
  85  * of the user's locale isolating most, if not all, of the locale-specific
  86  * information in resource bundles.
  87  *
  88  * <p>
  89  * This allows you to write programs that can:
  90  * <UL>
  91  * <LI> be easily localized, or translated, into different languages
  92  * <LI> handle multiple locales at once
  93  * <LI> be easily modified later to support even more locales
  94  * </UL>
  95  *
  96  * <P>
  97  * Resource bundles belong to families whose members share a common base
  98  * name, but whose names also have additional components that identify
  99  * their locales. For example, the base name of a family of resource
 100  * bundles might be "MyResources". The family should have a default
 101  * resource bundle which simply has the same name as its family -
 102  * "MyResources" - and will be used as the bundle of last resort if a
 103  * specific locale is not supported. The family can then provide as
 104  * many locale-specific members as needed, for example a German one
 105  * named "MyResources_de".
 106  *
 107  * <P>
 108  * Each resource bundle in a family contains the same items, but the items have
 109  * been translated for the locale represented by that resource bundle.
 110  * For example, both "MyResources" and "MyResources_de" may have a
 111  * <code>String</code> that's used on a button for canceling operations.
 112  * In "MyResources" the <code>String</code> may contain "Cancel" and in
 113  * "MyResources_de" it may contain "Abbrechen".
 114  *
 115  * <P>
 116  * If there are different resources for different countries, you
 117  * can make specializations: for example, "MyResources_de_CH" contains objects for
 118  * the German language (de) in Switzerland (CH). If you want to only
 119  * modify some of the resources
 120  * in the specialization, you can do so.
 121  *
 122  * <P>
 123  * When your program needs a locale-specific object, it loads
 124  * the <code>ResourceBundle</code> class using the
 125  * {@link #getBundle(java.lang.String, java.util.Locale) getBundle}
 126  * method:
 127  * <blockquote>
 128  * <pre>
 129  * ResourceBundle myResources =
 130  *      ResourceBundle.getBundle("MyResources", currentLocale);
 131  * </pre>
 132  * </blockquote>
 133  *
 134  * <P>
 135  * Resource bundles contain key/value pairs. The keys uniquely
 136  * identify a locale-specific object in the bundle. Here's an
 137  * example of a <code>ListResourceBundle</code> that contains
 138  * two key/value pairs:
 139  * <blockquote>
 140  * <pre>
 141  * public class MyResources extends ListResourceBundle {
 142  *     protected Object[][] getContents() {
 143  *         return new Object[][] {
 144  *             // LOCALIZE THE SECOND STRING OF EACH ARRAY (e.g., "OK")
 145  *             {"OkKey", "OK"},
 146  *             {"CancelKey", "Cancel"},
 147  *             // END OF MATERIAL TO LOCALIZE
 148  *        };
 149  *     }
 150  * }
 151  * </pre>
 152  * </blockquote>
 153  * Keys are always <code>String</code>s.
 154  * In this example, the keys are "OkKey" and "CancelKey".
 155  * In the above example, the values
 156  * are also <code>String</code>s--"OK" and "Cancel"--but
 157  * they don't have to be. The values can be any type of object.
 158  *
 159  * <P>
 160  * You retrieve an object from resource bundle using the appropriate
 161  * getter method. Because "OkKey" and "CancelKey"
 162  * are both strings, you would use <code>getString</code> to retrieve them:
 163  * <blockquote>
 164  * <pre>
 165  * button1 = new Button(myResources.getString("OkKey"));
 166  * button2 = new Button(myResources.getString("CancelKey"));
 167  * </pre>
 168  * </blockquote>
 169  * The getter methods all require the key as an argument and return
 170  * the object if found. If the object is not found, the getter method
 171  * throws a <code>MissingResourceException</code>.
 172  *
 173  * <P>
 174  * Besides <code>getString</code>, <code>ResourceBundle</code> also provides
 175  * a method for getting string arrays, <code>getStringArray</code>,
 176  * as well as a generic <code>getObject</code> method for any other
 177  * type of object. When using <code>getObject</code>, you'll
 178  * have to cast the result to the appropriate type. For example:
 179  * <blockquote>
 180  * <pre>
 181  * int[] myIntegers = (int[]) myResources.getObject("intList");
 182  * </pre>
 183  * </blockquote>
 184  *
 185  * <P>
 186  * The Java Platform provides two subclasses of <code>ResourceBundle</code>,
 187  * <code>ListResourceBundle</code> and <code>PropertyResourceBundle</code>,
 188  * that provide a fairly simple way to create resources.
 189  * As you saw briefly in a previous example, <code>ListResourceBundle</code>
 190  * manages its resource as a list of key/value pairs.
 191  * <code>PropertyResourceBundle</code> uses a properties file to manage
 192  * its resources.
 193  *
 194  * <p>
 195  * If <code>ListResourceBundle</code> or <code>PropertyResourceBundle</code>
 196  * do not suit your needs, you can write your own <code>ResourceBundle</code>
 197  * subclass.  Your subclasses must override two methods: <code>handleGetObject</code>
 198  * and <code>getKeys()</code>.
 199  *
 200  * <p>
 201  * The implementation of a {@code ResourceBundle} subclass must be thread-safe
 202  * if it's simultaneously used by multiple threads. The default implementations
 203  * of the non-abstract methods in this class, and the methods in the direct
 204  * known concrete subclasses {@code ListResourceBundle} and
 205  * {@code PropertyResourceBundle} are thread-safe.
 206  *
 207  * <h3><a id="bundleprovider">Resource Bundles in Named Modules</a></h3>
 208  *
 209  * When resource bundles are deployed in named modules, the following
 210  * module-specific requirements and restrictions are applied.
 211  *
 212  * <ul>
 213  * <li>Code in a named module that calls {@link #getBundle(String, Locale)}
 214  * will locate resource bundles in the caller's module (<em>caller module</em>).</li>
 215  * <li>If resource bundles are deployed in named modules separate from
 216  * the caller module, those resource bundles need to be loaded from service
 217  * providers of {@link ResourceBundleProvider}. The caller module must declare
 218  * "{@code uses}" and the service interface name is the concatenation of the
 219  * base name of the bundles and the string "{@code Provider}". The
 220  * <em>bundle provider modules</em> containing resource bundles must
 221  * declare "{@code provides}" with the service interface name and
 222  * its implementation class name. For example, if the base name is
 223  * "{@code com.example.app.MyResources}", the caller module must declare
 224  * "{@code uses com.example.app.MyResourcesProvider;}" and a module containing resource
 225  * bundles must declare "{@code provides com.example.app.MyResourcesProvider
 226  * with com.example.app.internal.MyResourcesProviderImpl;}"
 227  * where {@code com.example.app.internal.MyResourcesProviderImpl} is an
 228  * implementation class of {@code com.example.app.MyResourcesProvider}.</li>
 229  * <li>If you want to use non-standard formats in named modules, such as XML,
 230  * {@link ResourceBundleProvider} needs to be used.</li>
 231  * <li>The {@code getBundle} method with a {@code ClassLoader} may not be able to
 232  * find resource bundles using the given {@code ClassLoader} in named modules.
 233  * The {@code getBundle} method with a {@code Module} can be used, instead.</li>
 234  * <li>{@code ResourceBundle.Control} is <em>not</em> supported in named modules.
 235  * If the {@code getBundle} method with a {@code ResourceBundle.Control} is called
 236  * in a named module, the method will throw an {@code UnsupportedOperationException}.
 237  * Any service providers of {@link ResourceBundleControlProvider} are ignored in
 238  * named modules.
 239  * </li>
 240  * </ul>
 241  *
 242  * <h3><a id="RBP_support">ResourceBundleProvider Service Providers</a></h3>
 243  *
 244  * The {@code getBundle} factory methods load service providers of
 245  * {@link ResourceBundleProvider}, if available, using {@link ServiceLoader}.
 246  * The service type is designated by {@code basename+"Provider"}. For
 247  * example, if the base name is "{@code com.example.app.MyResources}", the service
 248  * type is {@code com.example.app.MyResourcesProvider}.
 249  * <p>
 250  * In named modules, the loaded service providers for the given base name are
 251  * used to load resource bundles. If no service provider is available, or if
 252  * none of the service providers returns a resource bundle and the caller module
 253  * doesn't have its own service provider, the {@code getBundle} factory method
 254  * searches for resource bundles that are local in the caller module and that
 255  * are visible to the class loader of the caller module.  The resource bundle
 256  * formats for local module searching are "java.class" and "java.properties".
 257  *
 258  * <h3>ResourceBundle.Control</h3>
 259  *
 260  * The {@link ResourceBundle.Control} class provides information necessary
 261  * to perform the bundle loading process by the <code>getBundle</code>
 262  * factory methods that take a <code>ResourceBundle.Control</code>
 263  * instance. You can implement your own subclass in order to enable
 264  * non-standard resource bundle formats, change the search strategy, or
 265  * define caching parameters. Refer to the descriptions of the class and the
 266  * {@link #getBundle(String, Locale, ClassLoader, Control) getBundle}
 267  * factory method for details.
 268  *
 269  * <p><a id="modify_default_behavior">For the {@code getBundle} factory</a>
 270  * methods that take no {@link Control} instance, their <a
 271  * href="#default_behavior"> default behavior</a> of resource bundle loading
 272  * can be modified with custom {@link
 273  * ResourceBundleControlProvider} implementations.
 274  * If any of the
 275  * providers provides a {@link Control} for the given base name, that {@link
 276  * Control} will be used instead of the default {@link Control}. If there is
 277  * more than one service provider for supporting the same base name,
 278  * the first one returned from {@link ServiceLoader} will be used.
 279  * A custom {@link Control} implementation is ignored by named modules.
 280  *
 281  * <h3>Cache Management</h3>
 282  *
 283  * Resource bundle instances created by the <code>getBundle</code> factory
 284  * methods are cached by default, and the factory methods return the same
 285  * resource bundle instance multiple times if it has been
 286  * cached. <code>getBundle</code> clients may clear the cache, manage the
 287  * lifetime of cached resource bundle instances using time-to-live values,
 288  * or specify not to cache resource bundle instances. Refer to the
 289  * descriptions of the {@linkplain #getBundle(String, Locale, ClassLoader,
 290  * Control) <code>getBundle</code> factory method}, {@link
 291  * #clearCache(ClassLoader) clearCache}, {@link
 292  * Control#getTimeToLive(String, Locale)
 293  * ResourceBundle.Control.getTimeToLive}, and {@link
 294  * Control#needsReload(String, Locale, String, ClassLoader, ResourceBundle,
 295  * long) ResourceBundle.Control.needsReload} for details.
 296  *
 297  * <h3>Example</h3>
 298  *
 299  * The following is a very simple example of a <code>ResourceBundle</code>
 300  * subclass, <code>MyResources</code>, that manages two resources (for a larger number of
 301  * resources you would probably use a <code>Map</code>).
 302  * Notice that you don't need to supply a value if
 303  * a "parent-level" <code>ResourceBundle</code> handles the same
 304  * key with the same value (as for the okKey below).
 305  * <blockquote>
 306  * <pre>
 307  * // default (English language, United States)
 308  * public class MyResources extends ResourceBundle {
 309  *     public Object handleGetObject(String key) {
 310  *         if (key.equals("okKey")) return "Ok";
 311  *         if (key.equals("cancelKey")) return "Cancel";
 312  *         return null;
 313  *     }
 314  *
 315  *     public Enumeration&lt;String&gt; getKeys() {
 316  *         return Collections.enumeration(keySet());
 317  *     }
 318  *
 319  *     // Overrides handleKeySet() so that the getKeys() implementation
 320  *     // can rely on the keySet() value.
 321  *     protected Set&lt;String&gt; handleKeySet() {
 322  *         return new HashSet&lt;String&gt;(Arrays.asList("okKey", "cancelKey"));
 323  *     }
 324  * }
 325  *
 326  * // German language
 327  * public class MyResources_de extends MyResources {
 328  *     public Object handleGetObject(String key) {
 329  *         // don't need okKey, since parent level handles it.
 330  *         if (key.equals("cancelKey")) return "Abbrechen";
 331  *         return null;
 332  *     }
 333  *
 334  *     protected Set&lt;String&gt; handleKeySet() {
 335  *         return new HashSet&lt;String&gt;(Arrays.asList("cancelKey"));
 336  *     }
 337  * }
 338  * </pre>
 339  * </blockquote>
 340  * You do not have to restrict yourself to using a single family of
 341  * <code>ResourceBundle</code>s. For example, you could have a set of bundles for
 342  * exception messages, <code>ExceptionResources</code>
 343  * (<code>ExceptionResources_fr</code>, <code>ExceptionResources_de</code>, ...),
 344  * and one for widgets, <code>WidgetResource</code> (<code>WidgetResources_fr</code>,
 345  * <code>WidgetResources_de</code>, ...); breaking up the resources however you like.
 346  *
 347  * @see ListResourceBundle
 348  * @see PropertyResourceBundle
 349  * @see MissingResourceException
 350  * @see ResourceBundleProvider
 351  * @since 1.1
 352  * @revised 9
 353  * @spec JPMS
 354  */
 355 public abstract class ResourceBundle {
 356 
 357     /** initial size of the bundle cache */
 358     private static final int INITIAL_CACHE_SIZE = 32;
 359 
 360     static {
 361         SharedSecrets.setJavaUtilResourceBundleAccess(
 362             new JavaUtilResourceBundleAccess() {
 363                 @Override
 364                 public void setParent(ResourceBundle bundle,
 365                                       ResourceBundle parent) {
 366                     bundle.setParent(parent);
 367                 }
 368 
 369                 @Override
 370                 public ResourceBundle getParent(ResourceBundle bundle) {
 371                     return bundle.parent;
 372                 }
 373 
 374                 @Override
 375                 public void setLocale(ResourceBundle bundle, Locale locale) {
 376                     bundle.locale = locale;
 377                 }
 378 
 379                 @Override
 380                 public void setName(ResourceBundle bundle, String name) {
 381                     bundle.name = name;
 382                 }
 383 
 384                 @Override
 385                 public ResourceBundle getBundle(String baseName, Locale locale, Module module) {
 386                     // use the given module as the caller to bypass the access check
 387                     return getBundleImpl(module, module,
 388                                          baseName, locale,
 389                                          getDefaultControl(module, baseName));
 390                 }
 391 
 392                 @Override
 393                 public ResourceBundle newResourceBundle(Class<? extends ResourceBundle> bundleClass) {
 394                     return ResourceBundleProviderHelper.newResourceBundle(bundleClass);
 395                 }
 396             });
 397     }
 398 
 399     /** constant indicating that no resource bundle exists */
 400     private static final ResourceBundle NONEXISTENT_BUNDLE = new ResourceBundle() {
 401             public Enumeration<String> getKeys() { return null; }
 402             protected Object handleGetObject(String key) { return null; }
 403             public String toString() { return "NONEXISTENT_BUNDLE"; }
 404         };
 405 
 406 
 407     /**
 408      * The cache is a map from cache keys (with bundle base name, locale, and
 409      * class loader) to either a resource bundle or NONEXISTENT_BUNDLE wrapped by a
 410      * BundleReference.
 411      *
 412      * The cache is a ConcurrentMap, allowing the cache to be searched
 413      * concurrently by multiple threads.  This will also allow the cache keys
 414      * to be reclaimed along with the ClassLoaders they reference.
 415      *
 416      * This variable would be better named "cache", but we keep the old
 417      * name for compatibility with some workarounds for bug 4212439.
 418      */
 419     private static final ConcurrentMap<CacheKey, BundleReference> cacheList
 420         = new ConcurrentHashMap<>(INITIAL_CACHE_SIZE);
 421 
 422     /**
 423      * Queue for reference objects referring to class loaders or bundles.
 424      */
 425     private static final ReferenceQueue<Object> referenceQueue = new ReferenceQueue<>();
 426 
 427     /**
 428      * Returns the base name of this bundle, if known, or {@code null} if unknown.
 429      *
 430      * If not null, then this is the value of the {@code baseName} parameter
 431      * that was passed to the {@code ResourceBundle.getBundle(...)} method
 432      * when the resource bundle was loaded.
 433      *
 434      * @return The base name of the resource bundle, as provided to and expected
 435      * by the {@code ResourceBundle.getBundle(...)} methods.
 436      *
 437      * @see #getBundle(java.lang.String, java.util.Locale, java.lang.ClassLoader)
 438      *
 439      * @since 1.8
 440      */
 441     public String getBaseBundleName() {
 442         return name;
 443     }
 444 
 445     /**
 446      * The parent bundle of this bundle.
 447      * The parent bundle is searched by {@link #getObject getObject}
 448      * when this bundle does not contain a particular resource.
 449      */
 450     protected ResourceBundle parent = null;
 451 
 452     /**
 453      * The locale for this bundle.
 454      */
 455     private Locale locale = null;
 456 
 457     /**
 458      * The base bundle name for this bundle.
 459      */
 460     private String name;
 461 
 462     /**
 463      * The flag indicating this bundle has expired in the cache.
 464      */
 465     private volatile boolean expired;
 466 
 467     /**
 468      * The back link to the cache key. null if this bundle isn't in
 469      * the cache (yet) or has expired.
 470      */
 471     private volatile CacheKey cacheKey;
 472 
 473     /**
 474      * A Set of the keys contained only in this ResourceBundle.
 475      */
 476     private volatile Set<String> keySet;
 477 
 478     /**
 479      * Sole constructor.  (For invocation by subclass constructors, typically
 480      * implicit.)
 481      */
 482     public ResourceBundle() {
 483     }
 484 
 485     /**
 486      * Gets a string for the given key from this resource bundle or one of its parents.
 487      * Calling this method is equivalent to calling
 488      * <blockquote>
 489      * <code>(String) {@link #getObject(java.lang.String) getObject}(key)</code>.
 490      * </blockquote>
 491      *
 492      * @param key the key for the desired string
 493      * @exception NullPointerException if <code>key</code> is <code>null</code>
 494      * @exception MissingResourceException if no object for the given key can be found
 495      * @exception ClassCastException if the object found for the given key is not a string
 496      * @return the string for the given key
 497      */
 498     public final String getString(String key) {
 499         return (String) getObject(key);
 500     }
 501 
 502     /**
 503      * Gets a string array for the given key from this resource bundle or one of its parents.
 504      * Calling this method is equivalent to calling
 505      * <blockquote>
 506      * <code>(String[]) {@link #getObject(java.lang.String) getObject}(key)</code>.
 507      * </blockquote>
 508      *
 509      * @param key the key for the desired string array
 510      * @exception NullPointerException if <code>key</code> is <code>null</code>
 511      * @exception MissingResourceException if no object for the given key can be found
 512      * @exception ClassCastException if the object found for the given key is not a string array
 513      * @return the string array for the given key
 514      */
 515     public final String[] getStringArray(String key) {
 516         return (String[]) getObject(key);
 517     }
 518 
 519     /**
 520      * Gets an object for the given key from this resource bundle or one of its parents.
 521      * This method first tries to obtain the object from this resource bundle using
 522      * {@link #handleGetObject(java.lang.String) handleGetObject}.
 523      * If not successful, and the parent resource bundle is not null,
 524      * it calls the parent's <code>getObject</code> method.
 525      * If still not successful, it throws a MissingResourceException.
 526      *
 527      * @param key the key for the desired object
 528      * @exception NullPointerException if <code>key</code> is <code>null</code>
 529      * @exception MissingResourceException if no object for the given key can be found
 530      * @return the object for the given key
 531      */
 532     public final Object getObject(String key) {
 533         Object obj = handleGetObject(key);
 534         if (obj == null) {
 535             if (parent != null) {
 536                 obj = parent.getObject(key);
 537             }
 538             if (obj == null) {
 539                 throw new MissingResourceException("Can't find resource for bundle "
 540                                                    +this.getClass().getName()
 541                                                    +", key "+key,
 542                                                    this.getClass().getName(),
 543                                                    key);
 544             }
 545         }
 546         return obj;
 547     }
 548 
 549     /**
 550      * Returns the locale of this resource bundle. This method can be used after a
 551      * call to getBundle() to determine whether the resource bundle returned really
 552      * corresponds to the requested locale or is a fallback.
 553      *
 554      * @return the locale of this resource bundle
 555      */
 556     public Locale getLocale() {
 557         return locale;
 558     }
 559 
 560     private static ClassLoader getLoader(Module module) {
 561         PrivilegedAction<ClassLoader> pa = module::getClassLoader;
 562         return AccessController.doPrivileged(pa);
 563     }
 564 
 565     /**
 566      * @param module a non-null-screened module form the {@link CacheKey#getModule()}.
 567      * @return the ClassLoader to use in {@link Control#needsReload}
 568      *         and {@link Control#newBundle}
 569      */
 570     private static ClassLoader getLoaderForControl(Module module) {
 571         ClassLoader loader = getLoader(module);
 572         return loader == null ? ClassLoader.getSystemClassLoader() : loader;
 573     }
 574 
 575     /**
 576      * Sets the parent bundle of this bundle.
 577      * The parent bundle is searched by {@link #getObject getObject}
 578      * when this bundle does not contain a particular resource.
 579      *
 580      * @param parent this bundle's parent bundle.
 581      */
 582     protected void setParent(ResourceBundle parent) {
 583         assert parent != NONEXISTENT_BUNDLE;
 584         this.parent = parent;
 585     }
 586 
 587     /**
 588      * Key used for cached resource bundles.  The key checks the base
 589      * name, the locale, the bundle module, and the caller module
 590      * to determine if the resource is a match to the requested one.
 591      * The base name, the locale and both modules must have a non-null value.
 592      */
 593     private static final class CacheKey {
 594         // These four are the actual keys for lookup in Map.
 595         private final String name;
 596         private volatile Locale locale;
 597         private final KeyElementReference<Module> moduleRef;
 598         private final KeyElementReference<Module> callerRef;
 599         // this is the part of hashCode that pertains to module and callerModule
 600         // which can be GCed..
 601         private final int modulesHash;
 602 
 603         // bundle format which is necessary for calling
 604         // Control.needsReload().
 605         private volatile String format;
 606 
 607         // These time values are in CacheKey so that NONEXISTENT_BUNDLE
 608         // doesn't need to be cloned for caching.
 609 
 610         // The time when the bundle has been loaded
 611         private volatile long loadTime;
 612 
 613         // The time when the bundle expires in the cache, or either
 614         // Control.TTL_DONT_CACHE or Control.TTL_NO_EXPIRATION_CONTROL.
 615         private volatile long expirationTime;
 616 
 617         // Placeholder for an error report by a Throwable
 618         private volatile Throwable cause;
 619 
 620         // ResourceBundleProviders for loading ResourceBundles
 621         private volatile ServiceLoader<ResourceBundleProvider> providers;
 622         private volatile boolean providersChecked;
 623 
 624         // Boolean.TRUE if the factory method caller provides a ResourceBundleProvier.
 625         private volatile Boolean callerHasProvider;
 626 
 627         CacheKey(String baseName, Locale locale, Module module, Module caller) {
 628             Objects.requireNonNull(module);
 629             Objects.requireNonNull(caller);
 630 
 631             this.name = baseName;
 632             this.locale = locale;
 633             this.moduleRef = new KeyElementReference<>(module, referenceQueue, this);
 634             this.callerRef = new KeyElementReference<>(caller, referenceQueue, this);
 635             this.modulesHash = module.hashCode() ^ caller.hashCode();
 636         }
 637 
 638         CacheKey(CacheKey src) {
 639             // Create References to src's modules
 640             this.moduleRef = new KeyElementReference<>(
 641                 Objects.requireNonNull(src.getModule()), referenceQueue, this);
 642             this.callerRef = new KeyElementReference<>(
 643                 Objects.requireNonNull(src.getCallerModule()), referenceQueue, this);
 644             // Copy fields from src. ResourceBundleProviders related fields
 645             // and "cause" should not be copied.
 646             this.name = src.name;
 647             this.locale = src.locale;
 648             this.modulesHash = src.modulesHash;
 649             this.format = src.format;
 650             this.loadTime = src.loadTime;
 651             this.expirationTime = src.expirationTime;
 652         }
 653 
 654         String getName() {
 655             return name;
 656         }
 657 
 658         Locale getLocale() {
 659             return locale;
 660         }
 661 
 662         CacheKey setLocale(Locale locale) {
 663             this.locale = locale;
 664             return this;
 665         }
 666 
 667         Module getModule() {
 668             return moduleRef.get();
 669         }
 670 
 671         Module getCallerModule() {
 672             return callerRef.get();
 673         }
 674 
 675         ServiceLoader<ResourceBundleProvider> getProviders() {
 676             if (!providersChecked) {
 677                 providers = getServiceLoader(getModule(), name);
 678                 providersChecked = true;
 679             }
 680             return providers;
 681         }
 682 
 683         boolean hasProviders() {
 684             return getProviders() != null;
 685         }
 686 
 687         boolean callerHasProvider() {
 688             return callerHasProvider == Boolean.TRUE;
 689         }
 690 
 691         @Override
 692         public boolean equals(Object other) {
 693             if (this == other) {
 694                 return true;
 695             }
 696             try {
 697                 final CacheKey otherEntry = (CacheKey)other;
 698                 //quick check to see if they are not equal
 699                 if (modulesHash != otherEntry.modulesHash) {
 700                     return false;
 701                 }
 702                 //are the names the same?
 703                 if (!name.equals(otherEntry.name)) {
 704                     return false;
 705                 }
 706                 // are the locales the same?
 707                 if (!locale.equals(otherEntry.locale)) {
 708                     return false;
 709                 }
 710                 // are modules and callerModules the same and non-null?
 711                 Module module = getModule();
 712                 Module caller = getCallerModule();
 713                 return ((module != null) && (module.equals(otherEntry.getModule())) &&
 714                         (caller != null) && (caller.equals(otherEntry.getCallerModule())));
 715             } catch (NullPointerException | ClassCastException e) {
 716             }
 717             return false;
 718         }
 719 
 720         @Override
 721         public int hashCode() {
 722             return (name.hashCode() << 3) ^ locale.hashCode() ^ modulesHash;
 723         }
 724 
 725         String getFormat() {
 726             return format;
 727         }
 728 
 729         void setFormat(String format) {
 730             this.format = format;
 731         }
 732 
 733         private void setCause(Throwable cause) {
 734             if (this.cause == null) {
 735                 this.cause = cause;
 736             } else {
 737                 // Override the cause if the previous one is
 738                 // ClassNotFoundException.
 739                 if (this.cause instanceof ClassNotFoundException) {
 740                     this.cause = cause;
 741                 }
 742             }
 743         }
 744 
 745         private Throwable getCause() {
 746             return cause;
 747         }
 748 
 749         @Override
 750         public String toString() {
 751             String l = locale.toString();
 752             if (l.length() == 0) {
 753                 if (locale.getVariant().length() != 0) {
 754                     l = "__" + locale.getVariant();
 755                 } else {
 756                     l = "\"\"";
 757                 }
 758             }
 759             return "CacheKey[" + name +
 760                    ", locale=" + l +
 761                    ", module=" + getModule() +
 762                    ", callerModule=" + getCallerModule() +
 763                    ", format=" + format +
 764                    "]";
 765         }
 766     }
 767 
 768     /**
 769      * The common interface to get a CacheKey in LoaderReference and
 770      * BundleReference.
 771      */
 772     private static interface CacheKeyReference {
 773         public CacheKey getCacheKey();
 774     }
 775 
 776     /**
 777      * References to a CacheKey element as a WeakReference so that it can be
 778      * garbage collected when nobody else is using it.
 779      */
 780     private static class KeyElementReference<T> extends WeakReference<T>
 781                                                 implements CacheKeyReference {
 782         private final CacheKey cacheKey;
 783 
 784         KeyElementReference(T referent, ReferenceQueue<Object> q, CacheKey key) {
 785             super(referent, q);
 786             cacheKey = key;
 787         }
 788 
 789         @Override
 790         public CacheKey getCacheKey() {
 791             return cacheKey;
 792         }
 793     }
 794 
 795     /**
 796      * References to bundles are soft references so that they can be garbage
 797      * collected when they have no hard references.
 798      */
 799     private static class BundleReference extends SoftReference<ResourceBundle>
 800                                          implements CacheKeyReference {
 801         private final CacheKey cacheKey;
 802 
 803         BundleReference(ResourceBundle referent, ReferenceQueue<Object> q, CacheKey key) {
 804             super(referent, q);
 805             cacheKey = key;
 806         }
 807 
 808         @Override
 809         public CacheKey getCacheKey() {
 810             return cacheKey;
 811         }
 812     }
 813 
 814     /**
 815      * Gets a resource bundle using the specified base name, the default locale,
 816      * and the caller's class loader. Calling this method is equivalent to calling
 817      * <blockquote>
 818      * <code>getBundle(baseName, Locale.getDefault(), this.getClass().getClassLoader())</code>,
 819      * </blockquote>
 820      * except that <code>getClassLoader()</code> is run with the security
 821      * privileges of <code>ResourceBundle</code>.
 822      * See {@link #getBundle(String, Locale, ClassLoader) getBundle}
 823      * for a complete description of the search and instantiation strategy.
 824      *
 825      * @param baseName the base name of the resource bundle, a fully qualified class name
 826      * @exception java.lang.NullPointerException
 827      *     if <code>baseName</code> is <code>null</code>
 828      * @exception MissingResourceException
 829      *     if no resource bundle for the specified base name can be found
 830      * @return a resource bundle for the given base name and the default locale
 831      */
 832     @CallerSensitive
 833     public static final ResourceBundle getBundle(String baseName)
 834     {
 835         Class<?> caller = Reflection.getCallerClass();
 836         return getBundleImpl(baseName, Locale.getDefault(),
 837                              caller, getDefaultControl(caller, baseName));
 838     }
 839 
 840     /**
 841      * Returns a resource bundle using the specified base name, the
 842      * default locale and the specified control. Calling this method
 843      * is equivalent to calling
 844      * <pre>
 845      * getBundle(baseName, Locale.getDefault(),
 846      *           this.getClass().getClassLoader(), control),
 847      * </pre>
 848      * except that <code>getClassLoader()</code> is run with the security
 849      * privileges of <code>ResourceBundle</code>.  See {@link
 850      * #getBundle(String, Locale, ClassLoader, Control) getBundle} for the
 851      * complete description of the resource bundle loading process with a
 852      * <code>ResourceBundle.Control</code>.
 853      *
 854      * @param baseName
 855      *        the base name of the resource bundle, a fully qualified class
 856      *        name
 857      * @param control
 858      *        the control which gives information for the resource bundle
 859      *        loading process
 860      * @return a resource bundle for the given base name and the default locale
 861      * @throws NullPointerException
 862      *         if <code>baseName</code> or <code>control</code> is
 863      *         <code>null</code>
 864      * @throws MissingResourceException
 865      *         if no resource bundle for the specified base name can be found
 866      * @throws IllegalArgumentException
 867      *         if the given <code>control</code> doesn't perform properly
 868      *         (e.g., <code>control.getCandidateLocales</code> returns null.)
 869      *         Note that validation of <code>control</code> is performed as
 870      *         needed.
 871      * @throws UnsupportedOperationException
 872      *         if this method is called in a named module
 873      * @since 1.6
 874      * @revised 9
 875      * @spec JPMS
 876      */
 877     @CallerSensitive
 878     public static final ResourceBundle getBundle(String baseName,
 879                                                  Control control) {
 880         Class<?> caller = Reflection.getCallerClass();
 881         Locale targetLocale = Locale.getDefault();
 882         checkNamedModule(caller);
 883         return getBundleImpl(baseName, targetLocale, caller, control);
 884     }
 885 
 886     /**
 887      * Gets a resource bundle using the specified base name and locale,
 888      * and the caller's class loader. Calling this method is equivalent to calling
 889      * <blockquote>
 890      * <code>getBundle(baseName, locale, this.getClass().getClassLoader())</code>,
 891      * </blockquote>
 892      * except that <code>getClassLoader()</code> is run with the security
 893      * privileges of <code>ResourceBundle</code>.
 894      * See {@link #getBundle(String, Locale, ClassLoader) getBundle}
 895      * for a complete description of the search and instantiation strategy.
 896      *
 897      * @param baseName
 898      *        the base name of the resource bundle, a fully qualified class name
 899      * @param locale
 900      *        the locale for which a resource bundle is desired
 901      * @exception NullPointerException
 902      *        if <code>baseName</code> or <code>locale</code> is <code>null</code>
 903      * @exception MissingResourceException
 904      *        if no resource bundle for the specified base name can be found
 905      * @return a resource bundle for the given base name and locale
 906      */
 907     @CallerSensitive
 908     public static final ResourceBundle getBundle(String baseName,
 909                                                  Locale locale)
 910     {
 911         Class<?> caller = Reflection.getCallerClass();
 912         return getBundleImpl(baseName, locale,
 913                              caller, getDefaultControl(caller, baseName));
 914     }
 915 
 916     /**
 917      * Gets a resource bundle using the specified base name and the default locale
 918      * on behalf of the specified module. This method is equivalent to calling
 919      * <blockquote>
 920      * <code>getBundle(baseName, Locale.getDefault(), module)</code>
 921      * </blockquote>
 922      *
 923      * <p> Resource bundles in named modules may be encapsulated.  When
 924      * the resource bundle is loaded from a provider, the caller module
 925      * must have an appropriate <i>uses</i> clause in its <i>module descriptor</i>
 926      * to declare that the module uses implementations of {@code "baseName"Provider}.
 927      * When the resource bundle is loaded from the specified module, it is
 928      * subject to the encapsulation rules specified by
 929      * {@link Module#getResourceAsStream Module.getResourceAsStream}.
 930      *
 931      * @param baseName the base name of the resource bundle,
 932      *                 a fully qualified class name
 933      * @param module   the module for which the resource bundle is searched
 934      * @throws NullPointerException
 935      *         if {@code baseName} or {@code module} is {@code null}
 936      * @throws SecurityException
 937      *         if a security manager exists and the caller is not the specified
 938      *         module and doesn't have {@code RuntimePermission("getClassLoader")}
 939      * @throws MissingResourceException
 940      *         if no resource bundle for the specified base name can be found in the
 941      *         specified module
 942      * @return a resource bundle for the given base name and the default locale
 943      * @since 9
 944      * @spec JPMS
 945      * @see ResourceBundleProvider
 946      */
 947     @CallerSensitive
 948     public static ResourceBundle getBundle(String baseName, Module module) {
 949         return getBundleFromModule(Reflection.getCallerClass(), module, baseName,
 950                                    Locale.getDefault(),
 951                                    getDefaultControl(module, baseName));
 952     }
 953 
 954     /**
 955      * Gets a resource bundle using the specified base name and locale
 956      * on behalf of the specified module.
 957      *
 958      * <p> Resource bundles in named modules may be encapsulated.  When
 959      * the resource bundle is loaded from a provider, the caller module
 960      * must have an appropriate <i>uses</i> clause in its <i>module descriptor</i>
 961      * to declare that the module uses implementations of {@code "baseName"Provider}.
 962      * When the resource bundle is loaded from the specified module, it is
 963      * subject to the encapsulation rules specified by
 964      * {@link Module#getResourceAsStream Module.getResourceAsStream}.
 965      *
 966      * <p>
 967      * If the given {@code module} is a named module, this method will
 968      * load the service providers for {@link java.util.spi.ResourceBundleProvider}
 969      * and also resource bundles that are local in the given module or that
 970      * are visible to the class loader of the given module (refer to the
 971      * <a href="#bundleprovider">Resource Bundles in Named Modules</a> section
 972      * for details).
 973      *
 974      * <p>
 975      * If the given {@code module} is an unnamed module, then this method is
 976      * equivalent to calling {@link #getBundle(String, Locale, ClassLoader)
 977      * getBundle(baseName, targetLocale, module.getClassLoader()} to load
 978      * resource bundles that are visible to the class loader of the given
 979      * unnamed module. Custom {@link java.util.spi.ResourceBundleControlProvider}
 980      * implementations, if present, will only be invoked if the specified
 981      * module is an unnamed module.
 982      *
 983      * @param baseName the base name of the resource bundle,
 984      *                 a fully qualified class name
 985      * @param targetLocale the locale for which a resource bundle is desired
 986      * @param module   the module for which the resource bundle is searched
 987      * @throws NullPointerException
 988      *         if {@code baseName}, {@code targetLocale}, or {@code module} is
 989      *         {@code null}
 990      * @throws SecurityException
 991      *         if a security manager exists and the caller is not the specified
 992      *         module and doesn't have {@code RuntimePermission("getClassLoader")}
 993      * @throws MissingResourceException
 994      *         if no resource bundle for the specified base name and locale can
 995      *         be found in the specified {@code module}
 996      * @return a resource bundle for the given base name and locale in the module
 997      * @since 9
 998      * @spec JPMS
 999      */
1000     @CallerSensitive
1001     public static ResourceBundle getBundle(String baseName, Locale targetLocale, Module module) {
1002         return getBundleFromModule(Reflection.getCallerClass(), module, baseName, targetLocale,
1003                                    getDefaultControl(module, baseName));
1004     }
1005 
1006     /**
1007      * Returns a resource bundle using the specified base name, target
1008      * locale and control, and the caller's class loader. Calling this
1009      * method is equivalent to calling
1010      * <pre>
1011      * getBundle(baseName, targetLocale, this.getClass().getClassLoader(),
1012      *           control),
1013      * </pre>
1014      * except that <code>getClassLoader()</code> is run with the security
1015      * privileges of <code>ResourceBundle</code>.  See {@link
1016      * #getBundle(String, Locale, ClassLoader, Control) getBundle} for the
1017      * complete description of the resource bundle loading process with a
1018      * <code>ResourceBundle.Control</code>.
1019      *
1020      * @param baseName
1021      *        the base name of the resource bundle, a fully qualified
1022      *        class name
1023      * @param targetLocale
1024      *        the locale for which a resource bundle is desired
1025      * @param control
1026      *        the control which gives information for the resource
1027      *        bundle loading process
1028      * @return a resource bundle for the given base name and a
1029      *         <code>Locale</code> in <code>locales</code>
1030      * @throws NullPointerException
1031      *         if <code>baseName</code>, <code>locales</code> or
1032      *         <code>control</code> is <code>null</code>
1033      * @throws MissingResourceException
1034      *         if no resource bundle for the specified base name in any
1035      *         of the <code>locales</code> can be found.
1036      * @throws IllegalArgumentException
1037      *         if the given <code>control</code> doesn't perform properly
1038      *         (e.g., <code>control.getCandidateLocales</code> returns null.)
1039      *         Note that validation of <code>control</code> is performed as
1040      *         needed.
1041      * @throws UnsupportedOperationException
1042      *         if this method is called in a named module
1043      * @since 1.6
1044      * @revised 9
1045      * @spec JPMS
1046      */
1047     @CallerSensitive
1048     public static final ResourceBundle getBundle(String baseName, Locale targetLocale,
1049                                                  Control control) {
1050         Class<?> caller = Reflection.getCallerClass();
1051         checkNamedModule(caller);
1052         return getBundleImpl(baseName, targetLocale, caller, control);
1053     }
1054 
1055     /**
1056      * Gets a resource bundle using the specified base name, locale, and class
1057      * loader.
1058      *
1059      * <p>This method behaves the same as calling
1060      * {@link #getBundle(String, Locale, ClassLoader, Control)} passing a
1061      * default instance of {@link Control} unless another {@link Control} is
1062      * provided with the {@link ResourceBundleControlProvider} SPI. Refer to the
1063      * description of <a href="#modify_default_behavior">modifying the default
1064      * behavior</a>.
1065      *
1066      * <p><a id="default_behavior">The following describes the default
1067      * behavior</a>.
1068      *
1069      * <p>
1070      * Resource bundles in a named module are private to that module.  If
1071      * the caller is in a named module, this method will find resource bundles
1072      * from the service providers of {@link java.util.spi.ResourceBundleProvider}
1073      * and also find resource bundles that are in the caller's module or
1074      * that are visible to the given class loader.
1075      * If the caller is in a named module and the given {@code loader} is
1076      * different than the caller's class loader, or if the caller is not in
1077      * a named module, this method will not find resource bundles from named
1078      * modules.
1079      *
1080      * <p><code>getBundle</code> uses the base name, the specified locale, and
1081      * the default locale (obtained from {@link java.util.Locale#getDefault()
1082      * Locale.getDefault}) to generate a sequence of <a
1083      * id="candidates"><em>candidate bundle names</em></a>.  If the specified
1084      * locale's language, script, country, and variant are all empty strings,
1085      * then the base name is the only candidate bundle name.  Otherwise, a list
1086      * of candidate locales is generated from the attribute values of the
1087      * specified locale (language, script, country and variant) and appended to
1088      * the base name.  Typically, this will look like the following:
1089      *
1090      * <pre>
1091      *     baseName + "_" + language + "_" + script + "_" + country + "_" + variant
1092      *     baseName + "_" + language + "_" + script + "_" + country
1093      *     baseName + "_" + language + "_" + script
1094      *     baseName + "_" + language + "_" + country + "_" + variant
1095      *     baseName + "_" + language + "_" + country
1096      *     baseName + "_" + language
1097      * </pre>
1098      *
1099      * <p>Candidate bundle names where the final component is an empty string
1100      * are omitted, along with the underscore.  For example, if country is an
1101      * empty string, the second and the fifth candidate bundle names above
1102      * would be omitted.  Also, if script is an empty string, the candidate names
1103      * including script are omitted.  For example, a locale with language "de"
1104      * and variant "JAVA" will produce candidate names with base name
1105      * "MyResource" below.
1106      *
1107      * <pre>
1108      *     MyResource_de__JAVA
1109      *     MyResource_de
1110      * </pre>
1111      *
1112      * In the case that the variant contains one or more underscores ('_'), a
1113      * sequence of bundle names generated by truncating the last underscore and
1114      * the part following it is inserted after a candidate bundle name with the
1115      * original variant.  For example, for a locale with language "en", script
1116      * "Latn, country "US" and variant "WINDOWS_VISTA", and bundle base name
1117      * "MyResource", the list of candidate bundle names below is generated:
1118      *
1119      * <pre>
1120      * MyResource_en_Latn_US_WINDOWS_VISTA
1121      * MyResource_en_Latn_US_WINDOWS
1122      * MyResource_en_Latn_US
1123      * MyResource_en_Latn
1124      * MyResource_en_US_WINDOWS_VISTA
1125      * MyResource_en_US_WINDOWS
1126      * MyResource_en_US
1127      * MyResource_en
1128      * </pre>
1129      *
1130      * <blockquote><b>Note:</b> For some <code>Locale</code>s, the list of
1131      * candidate bundle names contains extra names, or the order of bundle names
1132      * is slightly modified.  See the description of the default implementation
1133      * of {@link Control#getCandidateLocales(String, Locale)
1134      * getCandidateLocales} for details.</blockquote>
1135      *
1136      * <p><code>getBundle</code> then iterates over the candidate bundle names
1137      * to find the first one for which it can <em>instantiate</em> an actual
1138      * resource bundle. It uses the default controls' {@link Control#getFormats
1139      * getFormats} method, which generates two bundle names for each generated
1140      * name, the first a class name and the second a properties file name. For
1141      * each candidate bundle name, it attempts to create a resource bundle:
1142      *
1143      * <ul><li>First, it attempts to load a class using the generated class name.
1144      * If such a class can be found and loaded using the specified class
1145      * loader, is assignment compatible with ResourceBundle, is accessible from
1146      * ResourceBundle, and can be instantiated, <code>getBundle</code> creates a
1147      * new instance of this class and uses it as the <em>result resource
1148      * bundle</em>.
1149      *
1150      * <li>Otherwise, <code>getBundle</code> attempts to locate a property
1151      * resource file using the generated properties file name.  It generates a
1152      * path name from the candidate bundle name by replacing all "." characters
1153      * with "/" and appending the string ".properties".  It attempts to find a
1154      * "resource" with this name using {@link
1155      * java.lang.ClassLoader#getResource(java.lang.String)
1156      * ClassLoader.getResource}.  (Note that a "resource" in the sense of
1157      * <code>getResource</code> has nothing to do with the contents of a
1158      * resource bundle, it is just a container of data, such as a file.)  If it
1159      * finds a "resource", it attempts to create a new {@link
1160      * PropertyResourceBundle} instance from its contents.  If successful, this
1161      * instance becomes the <em>result resource bundle</em>.  </ul>
1162      *
1163      * <p>This continues until a result resource bundle is instantiated or the
1164      * list of candidate bundle names is exhausted.  If no matching resource
1165      * bundle is found, the default control's {@link Control#getFallbackLocale
1166      * getFallbackLocale} method is called, which returns the current default
1167      * locale.  A new sequence of candidate locale names is generated using this
1168      * locale and searched again, as above.
1169      *
1170      * <p>If still no result bundle is found, the base name alone is looked up. If
1171      * this still fails, a <code>MissingResourceException</code> is thrown.
1172      *
1173      * <p><a id="parent_chain"> Once a result resource bundle has been found,
1174      * its <em>parent chain</em> is instantiated</a>.  If the result bundle already
1175      * has a parent (perhaps because it was returned from a cache) the chain is
1176      * complete.
1177      *
1178      * <p>Otherwise, <code>getBundle</code> examines the remainder of the
1179      * candidate locale list that was used during the pass that generated the
1180      * result resource bundle.  (As before, candidate bundle names where the
1181      * final component is an empty string are omitted.)  When it comes to the
1182      * end of the candidate list, it tries the plain bundle name.  With each of the
1183      * candidate bundle names it attempts to instantiate a resource bundle (first
1184      * looking for a class and then a properties file, as described above).
1185      *
1186      * <p>Whenever it succeeds, it calls the previously instantiated resource
1187      * bundle's {@link #setParent(java.util.ResourceBundle) setParent} method
1188      * with the new resource bundle.  This continues until the list of names
1189      * is exhausted or the current bundle already has a non-null parent.
1190      *
1191      * <p>Once the parent chain is complete, the bundle is returned.
1192      *
1193      * <p><b>Note:</b> <code>getBundle</code> caches instantiated resource
1194      * bundles and might return the same resource bundle instance multiple times.
1195      *
1196      * <p><b>Note:</b>The <code>baseName</code> argument should be a fully
1197      * qualified class name. However, for compatibility with earlier versions,
1198      * Sun's Java SE Runtime Environments do not verify this, and so it is
1199      * possible to access <code>PropertyResourceBundle</code>s by specifying a
1200      * path name (using "/") instead of a fully qualified class name (using
1201      * ".").
1202      *
1203      * <p><a id="default_behavior_example">
1204      * <strong>Example:</strong></a>
1205      * <p>
1206      * The following class and property files are provided:
1207      * <pre>
1208      *     MyResources.class
1209      *     MyResources.properties
1210      *     MyResources_fr.properties
1211      *     MyResources_fr_CH.class
1212      *     MyResources_fr_CH.properties
1213      *     MyResources_en.properties
1214      *     MyResources_es_ES.class
1215      * </pre>
1216      *
1217      * The contents of all files are valid (that is, public non-abstract
1218      * subclasses of <code>ResourceBundle</code> for the ".class" files,
1219      * syntactically correct ".properties" files).  The default locale is
1220      * <code>Locale("en", "GB")</code>.
1221      *
1222      * <p>Calling <code>getBundle</code> with the locale arguments below will
1223      * instantiate resource bundles as follows:
1224      *
1225      * <table class="borderless">
1226      * <caption style="display:none">getBundle() locale to resource bundle mapping</caption>
1227      * <tbody>
1228      * <tr><td>Locale("fr", "CH")</td><td>MyResources_fr_CH.class, parent MyResources_fr.properties, parent MyResources.class</td></tr>
1229      * <tr><td>Locale("fr", "FR")</td><td>MyResources_fr.properties, parent MyResources.class</td></tr>
1230      * <tr><td>Locale("de", "DE")</td><td>MyResources_en.properties, parent MyResources.class</td></tr>
1231      * <tr><td>Locale("en", "US")</td><td>MyResources_en.properties, parent MyResources.class</td></tr>
1232      * <tr><td>Locale("es", "ES")</td><td>MyResources_es_ES.class, parent MyResources.class</td></tr>
1233      * </tbody>
1234      * </table>
1235      *
1236      * <p>The file MyResources_fr_CH.properties is never used because it is
1237      * hidden by the MyResources_fr_CH.class. Likewise, MyResources.properties
1238      * is also hidden by MyResources.class.
1239      *
1240      * @apiNote If the caller module is a named module and the given
1241      * {@code loader} is the caller module's class loader, this method is
1242      * equivalent to {@code getBundle(baseName, locale)}; otherwise, it will not
1243      * find resource bundles from named modules.
1244      * Use {@link #getBundle(String, Locale, Module)} to load resource bundles
1245      * on behalf on a specific module instead.
1246      *
1247      * @param baseName the base name of the resource bundle, a fully qualified class name
1248      * @param locale the locale for which a resource bundle is desired
1249      * @param loader the class loader from which to load the resource bundle
1250      * @return a resource bundle for the given base name and locale
1251      * @exception java.lang.NullPointerException
1252      *        if <code>baseName</code>, <code>locale</code>, or <code>loader</code> is <code>null</code>
1253      * @exception MissingResourceException
1254      *        if no resource bundle for the specified base name can be found
1255      * @since 1.2
1256      * @revised 9
1257      * @spec JPMS
1258      */
1259     @CallerSensitive
1260     public static ResourceBundle getBundle(String baseName, Locale locale,
1261                                            ClassLoader loader)
1262     {
1263         if (loader == null) {
1264             throw new NullPointerException();
1265         }
1266         Class<?> caller = Reflection.getCallerClass();
1267         return getBundleImpl(baseName, locale, caller, loader, getDefaultControl(caller, baseName));
1268     }
1269 
1270     /**
1271      * Returns a resource bundle using the specified base name, target
1272      * locale, class loader and control. Unlike the {@linkplain
1273      * #getBundle(String, Locale, ClassLoader) <code>getBundle</code>
1274      * factory methods with no <code>control</code> argument}, the given
1275      * <code>control</code> specifies how to locate and instantiate resource
1276      * bundles. Conceptually, the bundle loading process with the given
1277      * <code>control</code> is performed in the following steps.
1278      *
1279      * <ol>
1280      * <li>This factory method looks up the resource bundle in the cache for
1281      * the specified <code>baseName</code>, <code>targetLocale</code> and
1282      * <code>loader</code>.  If the requested resource bundle instance is
1283      * found in the cache and the time-to-live periods of the instance and
1284      * all of its parent instances have not expired, the instance is returned
1285      * to the caller. Otherwise, this factory method proceeds with the
1286      * loading process below.</li>
1287      *
1288      * <li>The {@link ResourceBundle.Control#getFormats(String)
1289      * control.getFormats} method is called to get resource bundle formats
1290      * to produce bundle or resource names. The strings
1291      * <code>"java.class"</code> and <code>"java.properties"</code>
1292      * designate class-based and {@linkplain PropertyResourceBundle
1293      * property}-based resource bundles, respectively. Other strings
1294      * starting with <code>"java."</code> are reserved for future extensions
1295      * and must not be used for application-defined formats. Other strings
1296      * designate application-defined formats.</li>
1297      *
1298      * <li>The {@link ResourceBundle.Control#getCandidateLocales(String,
1299      * Locale) control.getCandidateLocales} method is called with the target
1300      * locale to get a list of <em>candidate <code>Locale</code>s</em> for
1301      * which resource bundles are searched.</li>
1302      *
1303      * <li>The {@link ResourceBundle.Control#newBundle(String, Locale,
1304      * String, ClassLoader, boolean) control.newBundle} method is called to
1305      * instantiate a <code>ResourceBundle</code> for the base bundle name, a
1306      * candidate locale, and a format. (Refer to the note on the cache
1307      * lookup below.) This step is iterated over all combinations of the
1308      * candidate locales and formats until the <code>newBundle</code> method
1309      * returns a <code>ResourceBundle</code> instance or the iteration has
1310      * used up all the combinations. For example, if the candidate locales
1311      * are <code>Locale("de", "DE")</code>, <code>Locale("de")</code> and
1312      * <code>Locale("")</code> and the formats are <code>"java.class"</code>
1313      * and <code>"java.properties"</code>, then the following is the
1314      * sequence of locale-format combinations to be used to call
1315      * <code>control.newBundle</code>.
1316      *
1317      * <table class=striped style="width: 50%; text-align: left; margin-left: 40px;">
1318      * <caption style="display:none">locale-format combinations for newBundle</caption>
1319      * <thead>
1320      * <tr>
1321      * <td
1322      * style="vertical-align: top; text-align: left; font-weight: bold; width: 50%;"><code>Locale</code><br>
1323      * </td>
1324      * <td
1325      * style="vertical-align: top; text-align: left; font-weight: bold; width: 50%;"><code>format</code><br>
1326      * </td>
1327      * </tr>
1328      * </thead>
1329      * <tbody>
1330      * <tr>
1331      * <td style="vertical-align: top; width: 50%;"><code>Locale("de", "DE")</code><br>
1332      * </td>
1333      * <td style="vertical-align: top; width: 50%;"><code>java.class</code><br>
1334      * </td>
1335      * </tr>
1336      * <tr>
1337      * <td style="vertical-align: top; width: 50%;"><code>Locale("de", "DE")</code></td>
1338      * <td style="vertical-align: top; width: 50%;"><code>java.properties</code><br>
1339      * </td>
1340      * </tr>
1341      * <tr>
1342      * <td style="vertical-align: top; width: 50%;"><code>Locale("de")</code></td>
1343      * <td style="vertical-align: top; width: 50%;"><code>java.class</code></td>
1344      * </tr>
1345      * <tr>
1346      * <td style="vertical-align: top; width: 50%;"><code>Locale("de")</code></td>
1347      * <td style="vertical-align: top; width: 50%;"><code>java.properties</code></td>
1348      * </tr>
1349      * <tr>
1350      * <td style="vertical-align: top; width: 50%;"><code>Locale("")</code><br>
1351      * </td>
1352      * <td style="vertical-align: top; width: 50%;"><code>java.class</code></td>
1353      * </tr>
1354      * <tr>
1355      * <td style="vertical-align: top; width: 50%;"><code>Locale("")</code></td>
1356      * <td style="vertical-align: top; width: 50%;"><code>java.properties</code></td>
1357      * </tr>
1358      * </tbody>
1359      * </table>
1360      * </li>
1361      *
1362      * <li>If the previous step has found no resource bundle, proceed to
1363      * Step 6. If a bundle has been found that is a base bundle (a bundle
1364      * for <code>Locale("")</code>), and the candidate locale list only contained
1365      * <code>Locale("")</code>, return the bundle to the caller. If a bundle
1366      * has been found that is a base bundle, but the candidate locale list
1367      * contained locales other than Locale(""), put the bundle on hold and
1368      * proceed to Step 6. If a bundle has been found that is not a base
1369      * bundle, proceed to Step 7.</li>
1370      *
1371      * <li>The {@link ResourceBundle.Control#getFallbackLocale(String,
1372      * Locale) control.getFallbackLocale} method is called to get a fallback
1373      * locale (alternative to the current target locale) to try further
1374      * finding a resource bundle. If the method returns a non-null locale,
1375      * it becomes the next target locale and the loading process starts over
1376      * from Step 3. Otherwise, if a base bundle was found and put on hold in
1377      * a previous Step 5, it is returned to the caller now. Otherwise, a
1378      * MissingResourceException is thrown.</li>
1379      *
1380      * <li>At this point, we have found a resource bundle that's not the
1381      * base bundle. If this bundle set its parent during its instantiation,
1382      * it is returned to the caller. Otherwise, its <a
1383      * href="./ResourceBundle.html#parent_chain">parent chain</a> is
1384      * instantiated based on the list of candidate locales from which it was
1385      * found. Finally, the bundle is returned to the caller.</li>
1386      * </ol>
1387      *
1388      * <p>During the resource bundle loading process above, this factory
1389      * method looks up the cache before calling the {@link
1390      * Control#newBundle(String, Locale, String, ClassLoader, boolean)
1391      * control.newBundle} method.  If the time-to-live period of the
1392      * resource bundle found in the cache has expired, the factory method
1393      * calls the {@link ResourceBundle.Control#needsReload(String, Locale,
1394      * String, ClassLoader, ResourceBundle, long) control.needsReload}
1395      * method to determine whether the resource bundle needs to be reloaded.
1396      * If reloading is required, the factory method calls
1397      * <code>control.newBundle</code> to reload the resource bundle.  If
1398      * <code>control.newBundle</code> returns <code>null</code>, the factory
1399      * method puts a dummy resource bundle in the cache as a mark of
1400      * nonexistent resource bundles in order to avoid lookup overhead for
1401      * subsequent requests. Such dummy resource bundles are under the same
1402      * expiration control as specified by <code>control</code>.
1403      *
1404      * <p>All resource bundles loaded are cached by default. Refer to
1405      * {@link Control#getTimeToLive(String,Locale)
1406      * control.getTimeToLive} for details.
1407      *
1408      * <p>The following is an example of the bundle loading process with the
1409      * default <code>ResourceBundle.Control</code> implementation.
1410      *
1411      * <p>Conditions:
1412      * <ul>
1413      * <li>Base bundle name: <code>foo.bar.Messages</code>
1414      * <li>Requested <code>Locale</code>: {@link Locale#ITALY}</li>
1415      * <li>Default <code>Locale</code>: {@link Locale#FRENCH}</li>
1416      * <li>Available resource bundles:
1417      * <code>foo/bar/Messages_fr.properties</code> and
1418      * <code>foo/bar/Messages.properties</code></li>
1419      * </ul>
1420      *
1421      * <p>First, <code>getBundle</code> tries loading a resource bundle in
1422      * the following sequence.
1423      *
1424      * <ul>
1425      * <li>class <code>foo.bar.Messages_it_IT</code>
1426      * <li>file <code>foo/bar/Messages_it_IT.properties</code>
1427      * <li>class <code>foo.bar.Messages_it</code></li>
1428      * <li>file <code>foo/bar/Messages_it.properties</code></li>
1429      * <li>class <code>foo.bar.Messages</code></li>
1430      * <li>file <code>foo/bar/Messages.properties</code></li>
1431      * </ul>
1432      *
1433      * <p>At this point, <code>getBundle</code> finds
1434      * <code>foo/bar/Messages.properties</code>, which is put on hold
1435      * because it's the base bundle.  <code>getBundle</code> calls {@link
1436      * Control#getFallbackLocale(String, Locale)
1437      * control.getFallbackLocale("foo.bar.Messages", Locale.ITALY)} which
1438      * returns <code>Locale.FRENCH</code>. Next, <code>getBundle</code>
1439      * tries loading a bundle in the following sequence.
1440      *
1441      * <ul>
1442      * <li>class <code>foo.bar.Messages_fr</code></li>
1443      * <li>file <code>foo/bar/Messages_fr.properties</code></li>
1444      * <li>class <code>foo.bar.Messages</code></li>
1445      * <li>file <code>foo/bar/Messages.properties</code></li>
1446      * </ul>
1447      *
1448      * <p><code>getBundle</code> finds
1449      * <code>foo/bar/Messages_fr.properties</code> and creates a
1450      * <code>ResourceBundle</code> instance. Then, <code>getBundle</code>
1451      * sets up its parent chain from the list of the candidate locales.  Only
1452      * <code>foo/bar/Messages.properties</code> is found in the list and
1453      * <code>getBundle</code> creates a <code>ResourceBundle</code> instance
1454      * that becomes the parent of the instance for
1455      * <code>foo/bar/Messages_fr.properties</code>.
1456      *
1457      * @param baseName
1458      *        the base name of the resource bundle, a fully qualified
1459      *        class name
1460      * @param targetLocale
1461      *        the locale for which a resource bundle is desired
1462      * @param loader
1463      *        the class loader from which to load the resource bundle
1464      * @param control
1465      *        the control which gives information for the resource
1466      *        bundle loading process
1467      * @return a resource bundle for the given base name and locale
1468      * @throws NullPointerException
1469      *         if <code>baseName</code>, <code>targetLocale</code>,
1470      *         <code>loader</code>, or <code>control</code> is
1471      *         <code>null</code>
1472      * @throws MissingResourceException
1473      *         if no resource bundle for the specified base name can be found
1474      * @throws IllegalArgumentException
1475      *         if the given <code>control</code> doesn't perform properly
1476      *         (e.g., <code>control.getCandidateLocales</code> returns null.)
1477      *         Note that validation of <code>control</code> is performed as
1478      *         needed.
1479      * @throws UnsupportedOperationException
1480      *         if this method is called in a named module
1481      * @since 1.6
1482      * @revised 9
1483      * @spec JPMS
1484      */
1485     @CallerSensitive
1486     public static ResourceBundle getBundle(String baseName, Locale targetLocale,
1487                                            ClassLoader loader, Control control) {
1488         if (loader == null || control == null) {
1489             throw new NullPointerException();
1490         }
1491         Class<?> caller = Reflection.getCallerClass();
1492         checkNamedModule(caller);
1493         return getBundleImpl(baseName, targetLocale, caller, loader, control);
1494     }
1495 
1496     private static Control getDefaultControl(Class<?> caller, String baseName) {
1497         return getDefaultControl(caller.getModule(), baseName);
1498     }
1499 
1500     private static Control getDefaultControl(Module targetModule, String baseName) {
1501         return targetModule.isNamed() ?
1502             Control.INSTANCE :
1503             ResourceBundleControlProviderHolder.getControl(baseName);
1504     }
1505 
1506     private static class ResourceBundleControlProviderHolder {
1507         private static final PrivilegedAction<List<ResourceBundleControlProvider>> pa =
1508             () -> {
1509                 return Collections.unmodifiableList(
1510                     ServiceLoader.load(ResourceBundleControlProvider.class,
1511                                        ClassLoader.getSystemClassLoader()).stream()
1512                         .map(ServiceLoader.Provider::get)
1513                         .collect(Collectors.toList()));
1514             };
1515 
1516         private static final List<ResourceBundleControlProvider> CONTROL_PROVIDERS =
1517             AccessController.doPrivileged(pa);
1518 
1519         private static Control getControl(String baseName) {
1520             return CONTROL_PROVIDERS.isEmpty() ?
1521                 Control.INSTANCE :
1522                 CONTROL_PROVIDERS.stream()
1523                     .flatMap(provider -> Stream.ofNullable(provider.getControl(baseName)))
1524                     .findFirst()
1525                     .orElse(Control.INSTANCE);
1526         }
1527     }
1528 
1529     private static void checkNamedModule(Class<?> caller) {
1530         if (caller.getModule().isNamed()) {
1531             throw new UnsupportedOperationException(
1532                     "ResourceBundle.Control not supported in named modules");
1533         }
1534     }
1535 
1536     private static ResourceBundle getBundleImpl(String baseName,
1537                                                 Locale locale,
1538                                                 Class<?> caller,
1539                                                 Control control) {
1540         return getBundleImpl(baseName, locale, caller, caller.getClassLoader(), control);
1541     }
1542 
1543     /**
1544      * This method will find resource bundles using the legacy mechanism
1545      * if the caller is unnamed module or the given class loader is
1546      * not the class loader of the caller module getting the resource
1547      * bundle, i.e. find the class that is visible to the class loader
1548      * and properties from unnamed module.
1549      *
1550      * The module-aware resource bundle lookup mechanism will load
1551      * the service providers using the service loader mechanism
1552      * as well as properties local in the caller module.
1553      */
1554     private static ResourceBundle getBundleImpl(String baseName,
1555                                                 Locale locale,
1556                                                 Class<?> caller,
1557                                                 ClassLoader loader,
1558                                                 Control control) {
1559         if (caller == null) {
1560             throw new InternalError("null caller");
1561         }
1562         Module callerModule = caller.getModule();
1563 
1564         // get resource bundles for a named module only if loader is the module's class loader
1565         if (callerModule.isNamed() && loader == getLoader(callerModule)) {
1566             return getBundleImpl(callerModule, callerModule, baseName, locale, control);
1567         }
1568 
1569         // find resource bundles from unnamed module of given class loader
1570         // Java agent can add to the bootclasspath e.g. via
1571         // java.lang.instrument.Instrumentation and load classes in unnamed module.
1572         // It may call RB::getBundle that will end up here with loader == null.
1573         Module unnamedModule = loader != null
1574             ? loader.getUnnamedModule()
1575             : BootLoader.getUnnamedModule();
1576 
1577         return getBundleImpl(callerModule, unnamedModule, baseName, locale, control);
1578     }
1579 
1580     private static ResourceBundle getBundleFromModule(Class<?> caller,
1581                                                       Module module,
1582                                                       String baseName,
1583                                                       Locale locale,
1584                                                       Control control) {
1585         Objects.requireNonNull(module);
1586         Module callerModule = caller.getModule();
1587         if (callerModule != module) {
1588             SecurityManager sm = System.getSecurityManager();
1589             if (sm != null) {
1590                 sm.checkPermission(GET_CLASSLOADER_PERMISSION);
1591             }
1592         }
1593         return getBundleImpl(callerModule, module, baseName, locale, control);
1594     }
1595 
1596     private static ResourceBundle getBundleImpl(Module callerModule,
1597                                                 Module module,
1598                                                 String baseName,
1599                                                 Locale locale,
1600                                                 Control control) {
1601         if (locale == null || control == null) {
1602             throw new NullPointerException();
1603         }
1604 
1605         // We create a CacheKey here for use by this call. The base name
1606         // and modules will never change during the bundle loading
1607         // process. We have to make sure that the locale is set before
1608         // using it as a cache key.
1609         CacheKey cacheKey = new CacheKey(baseName, locale, module, callerModule);
1610         ResourceBundle bundle = null;
1611 
1612         // Quick lookup of the cache.
1613         BundleReference bundleRef = cacheList.get(cacheKey);
1614         if (bundleRef != null) {
1615             bundle = bundleRef.get();
1616             bundleRef = null;
1617         }
1618 
1619         // If this bundle and all of its parents are valid (not expired),
1620         // then return this bundle. If any of the bundles is expired, we
1621         // don't call control.needsReload here but instead drop into the
1622         // complete loading process below.
1623         if (isValidBundle(bundle) && hasValidParentChain(bundle)) {
1624             return bundle;
1625         }
1626 
1627         // No valid bundle was found in the cache, so we need to load the
1628         // resource bundle and its parents.
1629 
1630         boolean isKnownControl = (control == Control.INSTANCE) ||
1631                                    (control instanceof SingleFormatControl);
1632         List<String> formats = control.getFormats(baseName);
1633         if (!isKnownControl && !checkList(formats)) {
1634             throw new IllegalArgumentException("Invalid Control: getFormats");
1635         }
1636 
1637         ResourceBundle baseBundle = null;
1638         for (Locale targetLocale = locale;
1639              targetLocale != null;
1640              targetLocale = control.getFallbackLocale(baseName, targetLocale)) {
1641             List<Locale> candidateLocales = control.getCandidateLocales(baseName, targetLocale);
1642             if (!isKnownControl && !checkList(candidateLocales)) {
1643                 throw new IllegalArgumentException("Invalid Control: getCandidateLocales");
1644             }
1645 
1646             bundle = findBundle(callerModule, module, cacheKey,
1647                                 candidateLocales, formats, 0, control, baseBundle);
1648 
1649             // If the loaded bundle is the base bundle and exactly for the
1650             // requested locale or the only candidate locale, then take the
1651             // bundle as the resulting one. If the loaded bundle is the base
1652             // bundle, it's put on hold until we finish processing all
1653             // fallback locales.
1654             if (isValidBundle(bundle)) {
1655                 boolean isBaseBundle = Locale.ROOT.equals(bundle.locale);
1656                 if (!isBaseBundle || bundle.locale.equals(locale)
1657                     || (candidateLocales.size() == 1
1658                         && bundle.locale.equals(candidateLocales.get(0)))) {
1659                     break;
1660                 }
1661 
1662                 // If the base bundle has been loaded, keep the reference in
1663                 // baseBundle so that we can avoid any redundant loading in case
1664                 // the control specify not to cache bundles.
1665                 if (isBaseBundle && baseBundle == null) {
1666                     baseBundle = bundle;
1667                 }
1668             }
1669         }
1670 
1671         if (bundle == null) {
1672             if (baseBundle == null) {
1673                 throwMissingResourceException(baseName, locale, cacheKey.getCause());
1674             }
1675             bundle = baseBundle;
1676         }
1677 
1678         // keep callerModule and module reachable for as long as we are operating
1679         // with WeakReference(s) to them (in CacheKey)...
1680         Reference.reachabilityFence(callerModule);
1681         Reference.reachabilityFence(module);
1682 
1683         return bundle;
1684     }
1685 
1686     /**
1687      * Checks if the given <code>List</code> is not null, not empty,
1688      * not having null in its elements.
1689      */
1690     private static boolean checkList(List<?> a) {
1691         boolean valid = (a != null && !a.isEmpty());
1692         if (valid) {
1693             int size = a.size();
1694             for (int i = 0; valid && i < size; i++) {
1695                 valid = (a.get(i) != null);
1696             }
1697         }
1698         return valid;
1699     }
1700 
1701     private static ResourceBundle findBundle(Module callerModule,
1702                                              Module module,
1703                                              CacheKey cacheKey,
1704                                              List<Locale> candidateLocales,
1705                                              List<String> formats,
1706                                              int index,
1707                                              Control control,
1708                                              ResourceBundle baseBundle) {
1709         Locale targetLocale = candidateLocales.get(index);
1710         ResourceBundle parent = null;
1711         if (index != candidateLocales.size() - 1) {
1712             parent = findBundle(callerModule, module, cacheKey,
1713                                 candidateLocales, formats, index + 1,
1714                                 control, baseBundle);
1715         } else if (baseBundle != null && Locale.ROOT.equals(targetLocale)) {
1716             return baseBundle;
1717         }
1718 
1719         // Before we do the real loading work, see whether we need to
1720         // do some housekeeping: If references to modules or
1721         // resource bundles have been nulled out, remove all related
1722         // information from the cache.
1723         Object ref;
1724         while ((ref = referenceQueue.poll()) != null) {
1725             cacheList.remove(((CacheKeyReference)ref).getCacheKey());
1726         }
1727 
1728         // flag indicating the resource bundle has expired in the cache
1729         boolean expiredBundle = false;
1730 
1731         // First, look up the cache to see if it's in the cache, without
1732         // attempting to load bundle.
1733         cacheKey.setLocale(targetLocale);
1734         ResourceBundle bundle = findBundleInCache(cacheKey, control);
1735         if (isValidBundle(bundle)) {
1736             expiredBundle = bundle.expired;
1737             if (!expiredBundle) {
1738                 // If its parent is the one asked for by the candidate
1739                 // locales (the runtime lookup path), we can take the cached
1740                 // one. (If it's not identical, then we'd have to check the
1741                 // parent's parents to be consistent with what's been
1742                 // requested.)
1743                 if (bundle.parent == parent) {
1744                     return bundle;
1745                 }
1746                 // Otherwise, remove the cached one since we can't keep
1747                 // the same bundles having different parents.
1748                 BundleReference bundleRef = cacheList.get(cacheKey);
1749                 if (bundleRef != null && bundleRef.get() == bundle) {
1750                     cacheList.remove(cacheKey, bundleRef);
1751                 }
1752             }
1753         }
1754 
1755         if (bundle != NONEXISTENT_BUNDLE) {
1756             trace("findBundle: %d %s %s formats: %s%n", index, candidateLocales, cacheKey, formats);
1757             if (module.isNamed()) {
1758                 bundle = loadBundle(cacheKey, formats, control, module, callerModule);
1759             } else {
1760                 bundle = loadBundle(cacheKey, formats, control, expiredBundle);
1761             }
1762             if (bundle != null) {
1763                 if (bundle.parent == null) {
1764                     bundle.setParent(parent);
1765                 }
1766                 bundle.locale = targetLocale;
1767                 bundle = putBundleInCache(cacheKey, bundle, control);
1768                 return bundle;
1769             }
1770 
1771             // Put NONEXISTENT_BUNDLE in the cache as a mark that there's no bundle
1772             // instance for the locale.
1773             putBundleInCache(cacheKey, NONEXISTENT_BUNDLE, control);
1774         }
1775         return parent;
1776     }
1777 
1778     private static final String UNKNOWN_FORMAT = "";
1779 
1780 
1781     /*
1782      * Loads a ResourceBundle in named modules
1783      */
1784     private static ResourceBundle loadBundle(CacheKey cacheKey,
1785                                              List<String> formats,
1786                                              Control control,
1787                                              Module module,
1788                                              Module callerModule) {
1789         String baseName = cacheKey.getName();
1790         Locale targetLocale = cacheKey.getLocale();
1791 
1792         ResourceBundle bundle = null;
1793         if (cacheKey.hasProviders()) {
1794             if (callerModule == module) {
1795                 bundle = loadBundleFromProviders(baseName,
1796                                                  targetLocale,
1797                                                  cacheKey.getProviders(),
1798                                                  cacheKey);
1799             } else {
1800                 // load from provider if the caller module has access to the
1801                 // service type and also declares `uses`
1802                 ClassLoader loader = getLoader(module);
1803                 Class<ResourceBundleProvider> svc =
1804                     getResourceBundleProviderType(baseName, loader);
1805                 if (svc != null
1806                         && Reflection.verifyModuleAccess(callerModule, svc)
1807                         && callerModule.canUse(svc)) {
1808                     bundle = loadBundleFromProviders(baseName,
1809                                                      targetLocale,
1810                                                      cacheKey.getProviders(),
1811                                                      cacheKey);
1812                 }
1813             }
1814 
1815             if (bundle != null) {
1816                 cacheKey.setFormat(UNKNOWN_FORMAT);
1817             }
1818         }
1819 
1820         // If none of providers returned a bundle and the caller has no provider,
1821         // look up module-local bundles or from the class path
1822         if (bundle == null && !cacheKey.callerHasProvider()) {
1823             for (String format : formats) {
1824                 try {
1825                     switch (format) {
1826                     case "java.class":
1827                         bundle = ResourceBundleProviderHelper
1828                             .loadResourceBundle(callerModule, module, baseName, targetLocale);
1829 
1830                         break;
1831                     case "java.properties":
1832                         bundle = ResourceBundleProviderHelper
1833                             .loadPropertyResourceBundle(callerModule, module, baseName, targetLocale);
1834                         break;
1835                     default:
1836                         throw new InternalError("unexpected format: " + format);
1837                     }
1838 
1839                     if (bundle != null) {
1840                         cacheKey.setFormat(format);
1841                         break;
1842                     }
1843                 } catch (LinkageError|Exception e) {
1844                     cacheKey.setCause(e);
1845                 }
1846             }
1847         }
1848         return bundle;
1849     }
1850 
1851     /**
1852      * Returns a ServiceLoader that will find providers that are bound to
1853      * a given named module.
1854      */
1855     private static ServiceLoader<ResourceBundleProvider> getServiceLoader(Module module,
1856                                                                           String baseName)
1857     {
1858         if (!module.isNamed()) {
1859             return null;
1860         }
1861 
1862         ClassLoader loader = getLoader(module);
1863         Class<ResourceBundleProvider> service =
1864                 getResourceBundleProviderType(baseName, loader);
1865         if (service != null && Reflection.verifyModuleAccess(module, service)) {
1866             try {
1867                 // locate providers that are visible to the class loader
1868                 // ServiceConfigurationError will be thrown if the module
1869                 // does not declare `uses` the service type
1870                 return ServiceLoader.load(service, loader, module);
1871             } catch (ServiceConfigurationError e) {
1872                 // "uses" not declared
1873                 return null;
1874             }
1875         }
1876         return null;
1877     }
1878 
1879     /**
1880      * Returns the service type of the given baseName that is visible
1881      * to the given class loader
1882      */
1883     private static Class<ResourceBundleProvider>
1884             getResourceBundleProviderType(String baseName, ClassLoader loader)
1885     {
1886         // Look up <baseName> + "Provider"
1887         String providerName = baseName + "Provider";
1888         // Use the class loader of the getBundle caller so that the caller's
1889         // visibility of the provider type is checked.
1890         return AccessController.doPrivileged(
1891             new PrivilegedAction<>() {
1892                 @Override
1893                 public Class<ResourceBundleProvider> run() {
1894                     try {
1895                         Class<?> c = Class.forName(providerName, false, loader);
1896                         if (ResourceBundleProvider.class.isAssignableFrom(c)) {
1897                             @SuppressWarnings("unchecked")
1898                             Class<ResourceBundleProvider> s = (Class<ResourceBundleProvider>) c;
1899                             return s;
1900                         }
1901                     } catch (ClassNotFoundException e) {}
1902                     return null;
1903                 }
1904             });
1905     }
1906 
1907     /**
1908      * Loads ResourceBundle from service providers.
1909      */
1910     private static ResourceBundle loadBundleFromProviders(String baseName,
1911                                                           Locale locale,
1912                                                           ServiceLoader<ResourceBundleProvider> providers,
1913                                                           CacheKey cacheKey)
1914     {
1915         if (providers == null) return null;
1916 
1917         return AccessController.doPrivileged(
1918                 new PrivilegedAction<>() {
1919                     public ResourceBundle run() {
1920                         for (Iterator<ResourceBundleProvider> itr = providers.iterator(); itr.hasNext(); ) {
1921                             try {
1922                                 ResourceBundleProvider provider = itr.next();
1923                                 if (cacheKey != null && cacheKey.callerHasProvider == null
1924                                         && cacheKey.getModule() == provider.getClass().getModule()) {
1925                                     cacheKey.callerHasProvider = Boolean.TRUE;
1926                                 }
1927                                 ResourceBundle bundle = provider.getBundle(baseName, locale);
1928                                 trace("provider %s %s locale: %s bundle: %s%n", provider, baseName, locale, bundle);
1929                                 if (bundle != null) {
1930                                     return bundle;
1931                                 }
1932                             } catch (ServiceConfigurationError | SecurityException e) {
1933                                 if (cacheKey != null) {
1934                                     cacheKey.setCause(e);
1935                                 }
1936                             }
1937                         }
1938                         if (cacheKey != null && cacheKey.callerHasProvider == null) {
1939                             cacheKey.callerHasProvider = Boolean.FALSE;
1940                         }
1941                         return null;
1942                     }
1943                 });
1944 
1945     }
1946 
1947     /*
1948      * Legacy mechanism to load resource bundles
1949      */
1950     private static ResourceBundle loadBundle(CacheKey cacheKey,
1951                                              List<String> formats,
1952                                              Control control,
1953                                              boolean reload) {
1954 
1955         // Here we actually load the bundle in the order of formats
1956         // specified by the getFormats() value.
1957         Locale targetLocale = cacheKey.getLocale();
1958 
1959         Module module = cacheKey.getModule();
1960         if (module == null) {
1961             // should not happen
1962             throw new InternalError(
1963                 "Module for cache key: " + cacheKey + " has been GCed.");
1964         }
1965         ClassLoader loader = getLoaderForControl(module);
1966 
1967         ResourceBundle bundle = null;
1968         for (String format : formats) {
1969             try {
1970                 // ResourceBundle.Control.newBundle may be overridden
1971                 bundle = control.newBundle(cacheKey.getName(), targetLocale, format,
1972                                            loader, reload);
1973             } catch (LinkageError | Exception error) {
1974                 // We need to handle the LinkageError case due to
1975                 // inconsistent case-sensitivity in ClassLoader.
1976                 // See 6572242 for details.
1977                 cacheKey.setCause(error);
1978             }
1979             if (bundle != null) {
1980                 // Set the format in the cache key so that it can be
1981                 // used when calling needsReload later.
1982                 cacheKey.setFormat(format);
1983                 bundle.name = cacheKey.getName();
1984                 bundle.locale = targetLocale;
1985                 // Bundle provider might reuse instances. So we should make
1986                 // sure to clear the expired flag here.
1987                 bundle.expired = false;
1988                 break;
1989             }
1990         }
1991 
1992         return bundle;
1993     }
1994 
1995     private static boolean isValidBundle(ResourceBundle bundle) {
1996         return bundle != null && bundle != NONEXISTENT_BUNDLE;
1997     }
1998 
1999     /**
2000      * Determines whether any of resource bundles in the parent chain,
2001      * including the leaf, have expired.
2002      */
2003     private static boolean hasValidParentChain(ResourceBundle bundle) {
2004         long now = System.currentTimeMillis();
2005         while (bundle != null) {
2006             if (bundle.expired) {
2007                 return false;
2008             }
2009             CacheKey key = bundle.cacheKey;
2010             if (key != null) {
2011                 long expirationTime = key.expirationTime;
2012                 if (expirationTime >= 0 && expirationTime <= now) {
2013                     return false;
2014                 }
2015             }
2016             bundle = bundle.parent;
2017         }
2018         return true;
2019     }
2020 
2021     /**
2022      * Throw a MissingResourceException with proper message
2023      */
2024     private static void throwMissingResourceException(String baseName,
2025                                                       Locale locale,
2026                                                       Throwable cause) {
2027         // If the cause is a MissingResourceException, avoid creating
2028         // a long chain. (6355009)
2029         if (cause instanceof MissingResourceException) {
2030             cause = null;
2031         }
2032         throw new MissingResourceException("Can't find bundle for base name "
2033                                            + baseName + ", locale " + locale,
2034                                            baseName + "_" + locale, // className
2035                                            "",                      // key
2036                                            cause);
2037     }
2038 
2039     /**
2040      * Finds a bundle in the cache. Any expired bundles are marked as
2041      * `expired' and removed from the cache upon return.
2042      *
2043      * @param cacheKey the key to look up the cache
2044      * @param control the Control to be used for the expiration control
2045      * @return the cached bundle, or null if the bundle is not found in the
2046      * cache or its parent has expired. <code>bundle.expire</code> is true
2047      * upon return if the bundle in the cache has expired.
2048      */
2049     private static ResourceBundle findBundleInCache(CacheKey cacheKey,
2050                                                     Control control) {
2051         BundleReference bundleRef = cacheList.get(cacheKey);
2052         if (bundleRef == null) {
2053             return null;
2054         }
2055         ResourceBundle bundle = bundleRef.get();
2056         if (bundle == null) {
2057             return null;
2058         }
2059         ResourceBundle p = bundle.parent;
2060         assert p != NONEXISTENT_BUNDLE;
2061         // If the parent has expired, then this one must also expire. We
2062         // check only the immediate parent because the actual loading is
2063         // done from the root (base) to leaf (child) and the purpose of
2064         // checking is to propagate expiration towards the leaf. For
2065         // example, if the requested locale is ja_JP_JP and there are
2066         // bundles for all of the candidates in the cache, we have a list,
2067         //
2068         // base <- ja <- ja_JP <- ja_JP_JP
2069         //
2070         // If ja has expired, then it will reload ja and the list becomes a
2071         // tree.
2072         //
2073         // base <- ja (new)
2074         //  "   <- ja (expired) <- ja_JP <- ja_JP_JP
2075         //
2076         // When looking up ja_JP in the cache, it finds ja_JP in the cache
2077         // which references to the expired ja. Then, ja_JP is marked as
2078         // expired and removed from the cache. This will be propagated to
2079         // ja_JP_JP.
2080         //
2081         // Now, it's possible, for example, that while loading new ja_JP,
2082         // someone else has started loading the same bundle and finds the
2083         // base bundle has expired. Then, what we get from the first
2084         // getBundle call includes the expired base bundle. However, if
2085         // someone else didn't start its loading, we wouldn't know if the
2086         // base bundle has expired at the end of the loading process. The
2087         // expiration control doesn't guarantee that the returned bundle and
2088         // its parents haven't expired.
2089         //
2090         // We could check the entire parent chain to see if there's any in
2091         // the chain that has expired. But this process may never end. An
2092         // extreme case would be that getTimeToLive returns 0 and
2093         // needsReload always returns true.
2094         if (p != null && p.expired) {
2095             assert bundle != NONEXISTENT_BUNDLE;
2096             bundle.expired = true;
2097             bundle.cacheKey = null;
2098             cacheList.remove(cacheKey, bundleRef);
2099             bundle = null;
2100         } else {
2101             CacheKey key = bundleRef.getCacheKey();
2102             long expirationTime = key.expirationTime;
2103             if (!bundle.expired && expirationTime >= 0 &&
2104                 expirationTime <= System.currentTimeMillis()) {
2105                 // its TTL period has expired.
2106                 if (bundle != NONEXISTENT_BUNDLE) {
2107                     // Synchronize here to call needsReload to avoid
2108                     // redundant concurrent calls for the same bundle.
2109                     synchronized (bundle) {
2110                         expirationTime = key.expirationTime;
2111                         if (!bundle.expired && expirationTime >= 0 &&
2112                             expirationTime <= System.currentTimeMillis()) {
2113                             try {
2114                                 Module module = cacheKey.getModule();
2115                                 bundle.expired =
2116                                     module == null || // already GCed
2117                                     control.needsReload(key.getName(),
2118                                                         key.getLocale(),
2119                                                         key.getFormat(),
2120                                                         getLoaderForControl(module),
2121                                                         bundle,
2122                                                         key.loadTime);
2123                             } catch (Exception e) {
2124                                 cacheKey.setCause(e);
2125                             }
2126                             if (bundle.expired) {
2127                                 // If the bundle needs to be reloaded, then
2128                                 // remove the bundle from the cache, but
2129                                 // return the bundle with the expired flag
2130                                 // on.
2131                                 bundle.cacheKey = null;
2132                                 cacheList.remove(cacheKey, bundleRef);
2133                             } else {
2134                                 // Update the expiration control info. and reuse
2135                                 // the same bundle instance
2136                                 setExpirationTime(key, control);
2137                             }
2138                         }
2139                     }
2140                 } else {
2141                     // We just remove NONEXISTENT_BUNDLE from the cache.
2142                     cacheList.remove(cacheKey, bundleRef);
2143                     bundle = null;
2144                 }
2145             }
2146         }
2147         return bundle;
2148     }
2149 
2150     /**
2151      * Put a new bundle in the cache.
2152      *
2153      * @param cacheKey the key for the resource bundle
2154      * @param bundle the resource bundle to be put in the cache
2155      * @return the ResourceBundle for the cacheKey; if someone has put
2156      * the bundle before this call, the one found in the cache is
2157      * returned.
2158      */
2159     private static ResourceBundle putBundleInCache(CacheKey cacheKey,
2160                                                    ResourceBundle bundle,
2161                                                    Control control) {
2162         setExpirationTime(cacheKey, control);
2163         if (cacheKey.expirationTime != Control.TTL_DONT_CACHE) {
2164             CacheKey key = new CacheKey(cacheKey);
2165             BundleReference bundleRef = new BundleReference(bundle, referenceQueue, key);
2166             bundle.cacheKey = key;
2167 
2168             // Put the bundle in the cache if it's not been in the cache.
2169             BundleReference result = cacheList.putIfAbsent(key, bundleRef);
2170 
2171             // If someone else has put the same bundle in the cache before
2172             // us and it has not expired, we should use the one in the cache.
2173             if (result != null) {
2174                 ResourceBundle rb = result.get();
2175                 if (rb != null && !rb.expired) {
2176                     // Clear the back link to the cache key
2177                     bundle.cacheKey = null;
2178                     bundle = rb;
2179                     // Clear the reference in the BundleReference so that
2180                     // it won't be enqueued.
2181                     bundleRef.clear();
2182                 } else {
2183                     // Replace the invalid (garbage collected or expired)
2184                     // instance with the valid one.
2185                     cacheList.put(key, bundleRef);
2186                 }
2187             }
2188         }
2189         return bundle;
2190     }
2191 
2192     private static void setExpirationTime(CacheKey cacheKey, Control control) {
2193         long ttl = control.getTimeToLive(cacheKey.getName(),
2194                                          cacheKey.getLocale());
2195         if (ttl >= 0) {
2196             // If any expiration time is specified, set the time to be
2197             // expired in the cache.
2198             long now = System.currentTimeMillis();
2199             cacheKey.loadTime = now;
2200             cacheKey.expirationTime = now + ttl;
2201         } else if (ttl >= Control.TTL_NO_EXPIRATION_CONTROL) {
2202             cacheKey.expirationTime = ttl;
2203         } else {
2204             throw new IllegalArgumentException("Invalid Control: TTL=" + ttl);
2205         }
2206     }
2207 
2208     /**
2209      * Removes all resource bundles from the cache that have been loaded
2210      * by the caller's module.
2211      *
2212      * @since 1.6
2213      * @revised 9
2214      * @spec JPMS
2215      * @see ResourceBundle.Control#getTimeToLive(String,Locale)
2216      */
2217     @CallerSensitive
2218     public static final void clearCache() {
2219         Class<?> caller = Reflection.getCallerClass();
2220         cacheList.keySet().removeIf(
2221             key -> key.getCallerModule() == caller.getModule()
2222         );
2223     }
2224 
2225     /**
2226      * Removes all resource bundles from the cache that have been loaded
2227      * by the given class loader.
2228      *
2229      * @param loader the class loader
2230      * @exception NullPointerException if <code>loader</code> is null
2231      * @since 1.6
2232      * @see ResourceBundle.Control#getTimeToLive(String,Locale)
2233      */
2234     public static final void clearCache(ClassLoader loader) {
2235         Objects.requireNonNull(loader);
2236         cacheList.keySet().removeIf(
2237             key -> {
2238                 Module m;
2239                 return (m = key.getModule()) != null &&
2240                        getLoader(m) == loader;
2241             }
2242         );
2243     }
2244 
2245     /**
2246      * Gets an object for the given key from this resource bundle.
2247      * Returns null if this resource bundle does not contain an
2248      * object for the given key.
2249      *
2250      * @param key the key for the desired object
2251      * @exception NullPointerException if <code>key</code> is <code>null</code>
2252      * @return the object for the given key, or null
2253      */
2254     protected abstract Object handleGetObject(String key);
2255 
2256     /**
2257      * Returns an enumeration of the keys.
2258      *
2259      * @return an <code>Enumeration</code> of the keys contained in
2260      *         this <code>ResourceBundle</code> and its parent bundles.
2261      */
2262     public abstract Enumeration<String> getKeys();
2263 
2264     /**
2265      * Determines whether the given <code>key</code> is contained in
2266      * this <code>ResourceBundle</code> or its parent bundles.
2267      *
2268      * @param key
2269      *        the resource <code>key</code>
2270      * @return <code>true</code> if the given <code>key</code> is
2271      *        contained in this <code>ResourceBundle</code> or its
2272      *        parent bundles; <code>false</code> otherwise.
2273      * @exception NullPointerException
2274      *         if <code>key</code> is <code>null</code>
2275      * @since 1.6
2276      */
2277     public boolean containsKey(String key) {
2278         if (key == null) {
2279             throw new NullPointerException();
2280         }
2281         for (ResourceBundle rb = this; rb != null; rb = rb.parent) {
2282             if (rb.handleKeySet().contains(key)) {
2283                 return true;
2284             }
2285         }
2286         return false;
2287     }
2288 
2289     /**
2290      * Returns a <code>Set</code> of all keys contained in this
2291      * <code>ResourceBundle</code> and its parent bundles.
2292      *
2293      * @return a <code>Set</code> of all keys contained in this
2294      *         <code>ResourceBundle</code> and its parent bundles.
2295      * @since 1.6
2296      */
2297     public Set<String> keySet() {
2298         Set<String> keys = new HashSet<>();
2299         for (ResourceBundle rb = this; rb != null; rb = rb.parent) {
2300             keys.addAll(rb.handleKeySet());
2301         }
2302         return keys;
2303     }
2304 
2305     /**
2306      * Returns a <code>Set</code> of the keys contained <em>only</em>
2307      * in this <code>ResourceBundle</code>.
2308      *
2309      * <p>The default implementation returns a <code>Set</code> of the
2310      * keys returned by the {@link #getKeys() getKeys} method except
2311      * for the ones for which the {@link #handleGetObject(String)
2312      * handleGetObject} method returns <code>null</code>. Once the
2313      * <code>Set</code> has been created, the value is kept in this
2314      * <code>ResourceBundle</code> in order to avoid producing the
2315      * same <code>Set</code> in subsequent calls. Subclasses can
2316      * override this method for faster handling.
2317      *
2318      * @return a <code>Set</code> of the keys contained only in this
2319      *        <code>ResourceBundle</code>
2320      * @since 1.6
2321      */
2322     protected Set<String> handleKeySet() {
2323         if (keySet == null) {
2324             synchronized (this) {
2325                 if (keySet == null) {
2326                     Set<String> keys = new HashSet<>();
2327                     Enumeration<String> enumKeys = getKeys();
2328                     while (enumKeys.hasMoreElements()) {
2329                         String key = enumKeys.nextElement();
2330                         if (handleGetObject(key) != null) {
2331                             keys.add(key);
2332                         }
2333                     }
2334                     keySet = keys;
2335                 }
2336             }
2337         }
2338         return keySet;
2339     }
2340 
2341 
2342 
2343     /**
2344      * <code>ResourceBundle.Control</code> defines a set of callback methods
2345      * that are invoked by the {@link ResourceBundle#getBundle(String,
2346      * Locale, ClassLoader, Control) ResourceBundle.getBundle} factory
2347      * methods during the bundle loading process. In other words, a
2348      * <code>ResourceBundle.Control</code> collaborates with the factory
2349      * methods for loading resource bundles. The default implementation of
2350      * the callback methods provides the information necessary for the
2351      * factory methods to perform the <a
2352      * href="./ResourceBundle.html#default_behavior">default behavior</a>.
2353      * <a href="#note">Note that this class is not supported in named modules.</a>
2354      *
2355      * <p>In addition to the callback methods, the {@link
2356      * #toBundleName(String, Locale) toBundleName} and {@link
2357      * #toResourceName(String, String) toResourceName} methods are defined
2358      * primarily for convenience in implementing the callback
2359      * methods. However, the <code>toBundleName</code> method could be
2360      * overridden to provide different conventions in the organization and
2361      * packaging of localized resources.  The <code>toResourceName</code>
2362      * method is <code>final</code> to avoid use of wrong resource and class
2363      * name separators.
2364      *
2365      * <p>Two factory methods, {@link #getControl(List)} and {@link
2366      * #getNoFallbackControl(List)}, provide
2367      * <code>ResourceBundle.Control</code> instances that implement common
2368      * variations of the default bundle loading process.
2369      *
2370      * <p>The formats returned by the {@link Control#getFormats(String)
2371      * getFormats} method and candidate locales returned by the {@link
2372      * ResourceBundle.Control#getCandidateLocales(String, Locale)
2373      * getCandidateLocales} method must be consistent in all
2374      * <code>ResourceBundle.getBundle</code> invocations for the same base
2375      * bundle. Otherwise, the <code>ResourceBundle.getBundle</code> methods
2376      * may return unintended bundles. For example, if only
2377      * <code>"java.class"</code> is returned by the <code>getFormats</code>
2378      * method for the first call to <code>ResourceBundle.getBundle</code>
2379      * and only <code>"java.properties"</code> for the second call, then the
2380      * second call will return the class-based one that has been cached
2381      * during the first call.
2382      *
2383      * <p>A <code>ResourceBundle.Control</code> instance must be thread-safe
2384      * if it's simultaneously used by multiple threads.
2385      * <code>ResourceBundle.getBundle</code> does not synchronize to call
2386      * the <code>ResourceBundle.Control</code> methods. The default
2387      * implementations of the methods are thread-safe.
2388      *
2389      * <p>Applications can specify <code>ResourceBundle.Control</code>
2390      * instances returned by the <code>getControl</code> factory methods or
2391      * created from a subclass of <code>ResourceBundle.Control</code> to
2392      * customize the bundle loading process. The following are examples of
2393      * changing the default bundle loading process.
2394      *
2395      * <p><b>Example 1</b>
2396      *
2397      * <p>The following code lets <code>ResourceBundle.getBundle</code> look
2398      * up only properties-based resources.
2399      *
2400      * <pre>
2401      * import java.util.*;
2402      * import static java.util.ResourceBundle.Control.*;
2403      * ...
2404      * ResourceBundle bundle =
2405      *   ResourceBundle.getBundle("MyResources", new Locale("fr", "CH"),
2406      *                            ResourceBundle.Control.getControl(FORMAT_PROPERTIES));
2407      * </pre>
2408      *
2409      * Given the resource bundles in the <a
2410      * href="./ResourceBundle.html#default_behavior_example">example</a> in
2411      * the <code>ResourceBundle.getBundle</code> description, this
2412      * <code>ResourceBundle.getBundle</code> call loads
2413      * <code>MyResources_fr_CH.properties</code> whose parent is
2414      * <code>MyResources_fr.properties</code> whose parent is
2415      * <code>MyResources.properties</code>. (<code>MyResources_fr_CH.properties</code>
2416      * is not hidden, but <code>MyResources_fr_CH.class</code> is.)
2417      *
2418      * <p><b>Example 2</b>
2419      *
2420      * <p>The following is an example of loading XML-based bundles
2421      * using {@link Properties#loadFromXML(java.io.InputStream)
2422      * Properties.loadFromXML}.
2423      *
2424      * <pre>
2425      * ResourceBundle rb = ResourceBundle.getBundle("Messages",
2426      *     new ResourceBundle.Control() {
2427      *         public List&lt;String&gt; getFormats(String baseName) {
2428      *             if (baseName == null)
2429      *                 throw new NullPointerException();
2430      *             return Arrays.asList("xml");
2431      *         }
2432      *         public ResourceBundle newBundle(String baseName,
2433      *                                         Locale locale,
2434      *                                         String format,
2435      *                                         ClassLoader loader,
2436      *                                         boolean reload)
2437      *                          throws IllegalAccessException,
2438      *                                 InstantiationException,
2439      *                                 IOException {
2440      *             if (baseName == null || locale == null
2441      *                   || format == null || loader == null)
2442      *                 throw new NullPointerException();
2443      *             ResourceBundle bundle = null;
2444      *             if (format.equals("xml")) {
2445      *                 String bundleName = toBundleName(baseName, locale);
2446      *                 String resourceName = toResourceName(bundleName, format);
2447      *                 InputStream stream = null;
2448      *                 if (reload) {
2449      *                     URL url = loader.getResource(resourceName);
2450      *                     if (url != null) {
2451      *                         URLConnection connection = url.openConnection();
2452      *                         if (connection != null) {
2453      *                             // Disable caches to get fresh data for
2454      *                             // reloading.
2455      *                             connection.setUseCaches(false);
2456      *                             stream = connection.getInputStream();
2457      *                         }
2458      *                     }
2459      *                 } else {
2460      *                     stream = loader.getResourceAsStream(resourceName);
2461      *                 }
2462      *                 if (stream != null) {
2463      *                     BufferedInputStream bis = new BufferedInputStream(stream);
2464      *                     bundle = new XMLResourceBundle(bis);
2465      *                     bis.close();
2466      *                 }
2467      *             }
2468      *             return bundle;
2469      *         }
2470      *     });
2471      *
2472      * ...
2473      *
2474      * private static class XMLResourceBundle extends ResourceBundle {
2475      *     private Properties props;
2476      *     XMLResourceBundle(InputStream stream) throws IOException {
2477      *         props = new Properties();
2478      *         props.loadFromXML(stream);
2479      *     }
2480      *     protected Object handleGetObject(String key) {
2481      *         return props.getProperty(key);
2482      *     }
2483      *     public Enumeration&lt;String&gt; getKeys() {
2484      *         ...
2485      *     }
2486      * }
2487      * </pre>
2488      *
2489      * @apiNote <a id="note">{@code ResourceBundle.Control} is not supported
2490      * in named modules.</a> If the {@code ResourceBundle.getBundle} method with
2491      * a {@code ResourceBundle.Control} is called in a named module, the method
2492      * will throw an {@link UnsupportedOperationException}. Any service providers
2493      * of {@link ResourceBundleControlProvider} are ignored in named modules.
2494      *
2495      * @since 1.6
2496      * @revised 9
2497      * @spec JPMS
2498      * @see java.util.spi.ResourceBundleProvider
2499      */
2500     public static class Control {
2501         /**
2502          * The default format <code>List</code>, which contains the strings
2503          * <code>"java.class"</code> and <code>"java.properties"</code>, in
2504          * this order. This <code>List</code> is unmodifiable.
2505          *
2506          * @see #getFormats(String)
2507          */
2508         public static final List<String> FORMAT_DEFAULT
2509             = List.of("java.class", "java.properties");
2510 
2511         /**
2512          * The class-only format <code>List</code> containing
2513          * <code>"java.class"</code>. This <code>List</code> is unmodifiable.
2514          *
2515          * @see #getFormats(String)
2516          */
2517         public static final List<String> FORMAT_CLASS = List.of("java.class");
2518 
2519         /**
2520          * The properties-only format <code>List</code> containing
2521          * <code>"java.properties"</code>. This <code>List</code> is unmodifiable.
2522          *
2523          * @see #getFormats(String)
2524          */
2525         public static final List<String> FORMAT_PROPERTIES
2526             = List.of("java.properties");
2527 
2528         /**
2529          * The time-to-live constant for not caching loaded resource bundle
2530          * instances.
2531          *
2532          * @see #getTimeToLive(String, Locale)
2533          */
2534         public static final long TTL_DONT_CACHE = -1;
2535 
2536         /**
2537          * The time-to-live constant for disabling the expiration control
2538          * for loaded resource bundle instances in the cache.
2539          *
2540          * @see #getTimeToLive(String, Locale)
2541          */
2542         public static final long TTL_NO_EXPIRATION_CONTROL = -2;
2543 
2544         private static final Control INSTANCE = new Control();
2545 
2546         /**
2547          * Sole constructor. (For invocation by subclass constructors,
2548          * typically implicit.)
2549          */
2550         protected Control() {
2551         }
2552 
2553         /**
2554          * Returns a <code>ResourceBundle.Control</code> in which the {@link
2555          * #getFormats(String) getFormats} method returns the specified
2556          * <code>formats</code>. The <code>formats</code> must be equal to
2557          * one of {@link Control#FORMAT_PROPERTIES}, {@link
2558          * Control#FORMAT_CLASS} or {@link
2559          * Control#FORMAT_DEFAULT}. <code>ResourceBundle.Control</code>
2560          * instances returned by this method are singletons and thread-safe.
2561          *
2562          * <p>Specifying {@link Control#FORMAT_DEFAULT} is equivalent to
2563          * instantiating the <code>ResourceBundle.Control</code> class,
2564          * except that this method returns a singleton.
2565          *
2566          * @param formats
2567          *        the formats to be returned by the
2568          *        <code>ResourceBundle.Control.getFormats</code> method
2569          * @return a <code>ResourceBundle.Control</code> supporting the
2570          *        specified <code>formats</code>
2571          * @exception NullPointerException
2572          *        if <code>formats</code> is <code>null</code>
2573          * @exception IllegalArgumentException
2574          *        if <code>formats</code> is unknown
2575          */
2576         public static final Control getControl(List<String> formats) {
2577             if (formats.equals(Control.FORMAT_PROPERTIES)) {
2578                 return SingleFormatControl.PROPERTIES_ONLY;
2579             }
2580             if (formats.equals(Control.FORMAT_CLASS)) {
2581                 return SingleFormatControl.CLASS_ONLY;
2582             }
2583             if (formats.equals(Control.FORMAT_DEFAULT)) {
2584                 return Control.INSTANCE;
2585             }
2586             throw new IllegalArgumentException();
2587         }
2588 
2589         /**
2590          * Returns a <code>ResourceBundle.Control</code> in which the {@link
2591          * #getFormats(String) getFormats} method returns the specified
2592          * <code>formats</code> and the {@link
2593          * Control#getFallbackLocale(String, Locale) getFallbackLocale}
2594          * method returns <code>null</code>. The <code>formats</code> must
2595          * be equal to one of {@link Control#FORMAT_PROPERTIES}, {@link
2596          * Control#FORMAT_CLASS} or {@link Control#FORMAT_DEFAULT}.
2597          * <code>ResourceBundle.Control</code> instances returned by this
2598          * method are singletons and thread-safe.
2599          *
2600          * @param formats
2601          *        the formats to be returned by the
2602          *        <code>ResourceBundle.Control.getFormats</code> method
2603          * @return a <code>ResourceBundle.Control</code> supporting the
2604          *        specified <code>formats</code> with no fallback
2605          *        <code>Locale</code> support
2606          * @exception NullPointerException
2607          *        if <code>formats</code> is <code>null</code>
2608          * @exception IllegalArgumentException
2609          *        if <code>formats</code> is unknown
2610          */
2611         public static final Control getNoFallbackControl(List<String> formats) {
2612             if (formats.equals(Control.FORMAT_DEFAULT)) {
2613                 return NoFallbackControl.NO_FALLBACK;
2614             }
2615             if (formats.equals(Control.FORMAT_PROPERTIES)) {
2616                 return NoFallbackControl.PROPERTIES_ONLY_NO_FALLBACK;
2617             }
2618             if (formats.equals(Control.FORMAT_CLASS)) {
2619                 return NoFallbackControl.CLASS_ONLY_NO_FALLBACK;
2620             }
2621             throw new IllegalArgumentException();
2622         }
2623 
2624         /**
2625          * Returns a <code>List</code> of <code>String</code>s containing
2626          * formats to be used to load resource bundles for the given
2627          * <code>baseName</code>. The <code>ResourceBundle.getBundle</code>
2628          * factory method tries to load resource bundles with formats in the
2629          * order specified by the list. The list returned by this method
2630          * must have at least one <code>String</code>. The predefined
2631          * formats are <code>"java.class"</code> for class-based resource
2632          * bundles and <code>"java.properties"</code> for {@linkplain
2633          * PropertyResourceBundle properties-based} ones. Strings starting
2634          * with <code>"java."</code> are reserved for future extensions and
2635          * must not be used by application-defined formats.
2636          *
2637          * <p>It is not a requirement to return an immutable (unmodifiable)
2638          * <code>List</code>.  However, the returned <code>List</code> must
2639          * not be mutated after it has been returned by
2640          * <code>getFormats</code>.
2641          *
2642          * <p>The default implementation returns {@link #FORMAT_DEFAULT} so
2643          * that the <code>ResourceBundle.getBundle</code> factory method
2644          * looks up first class-based resource bundles, then
2645          * properties-based ones.
2646          *
2647          * @param baseName
2648          *        the base name of the resource bundle, a fully qualified class
2649          *        name
2650          * @return a <code>List</code> of <code>String</code>s containing
2651          *        formats for loading resource bundles.
2652          * @exception NullPointerException
2653          *        if <code>baseName</code> is null
2654          * @see #FORMAT_DEFAULT
2655          * @see #FORMAT_CLASS
2656          * @see #FORMAT_PROPERTIES
2657          */
2658         public List<String> getFormats(String baseName) {
2659             if (baseName == null) {
2660                 throw new NullPointerException();
2661             }
2662             return FORMAT_DEFAULT;
2663         }
2664 
2665         /**
2666          * Returns a <code>List</code> of <code>Locale</code>s as candidate
2667          * locales for <code>baseName</code> and <code>locale</code>. This
2668          * method is called by the <code>ResourceBundle.getBundle</code>
2669          * factory method each time the factory method tries finding a
2670          * resource bundle for a target <code>Locale</code>.
2671          *
2672          * <p>The sequence of the candidate locales also corresponds to the
2673          * runtime resource lookup path (also known as the <I>parent
2674          * chain</I>), if the corresponding resource bundles for the
2675          * candidate locales exist and their parents are not defined by
2676          * loaded resource bundles themselves.  The last element of the list
2677          * must be a {@linkplain Locale#ROOT root locale} if it is desired to
2678          * have the base bundle as the terminal of the parent chain.
2679          *
2680          * <p>If the given locale is equal to <code>Locale.ROOT</code> (the
2681          * root locale), a <code>List</code> containing only the root
2682          * <code>Locale</code> must be returned. In this case, the
2683          * <code>ResourceBundle.getBundle</code> factory method loads only
2684          * the base bundle as the resulting resource bundle.
2685          *
2686          * <p>It is not a requirement to return an immutable (unmodifiable)
2687          * <code>List</code>. However, the returned <code>List</code> must not
2688          * be mutated after it has been returned by
2689          * <code>getCandidateLocales</code>.
2690          *
2691          * <p>The default implementation returns a <code>List</code> containing
2692          * <code>Locale</code>s using the rules described below.  In the
2693          * description below, <em>L</em>, <em>S</em>, <em>C</em> and <em>V</em>
2694          * respectively represent non-empty language, script, country, and
2695          * variant.  For example, [<em>L</em>, <em>C</em>] represents a
2696          * <code>Locale</code> that has non-empty values only for language and
2697          * country.  The form <em>L</em>("xx") represents the (non-empty)
2698          * language value is "xx".  For all cases, <code>Locale</code>s whose
2699          * final component values are empty strings are omitted.
2700          *
2701          * <ol><li>For an input <code>Locale</code> with an empty script value,
2702          * append candidate <code>Locale</code>s by omitting the final component
2703          * one by one as below:
2704          *
2705          * <ul>
2706          * <li> [<em>L</em>, <em>C</em>, <em>V</em>] </li>
2707          * <li> [<em>L</em>, <em>C</em>] </li>
2708          * <li> [<em>L</em>] </li>
2709          * <li> <code>Locale.ROOT</code> </li>
2710          * </ul></li>
2711          *
2712          * <li>For an input <code>Locale</code> with a non-empty script value,
2713          * append candidate <code>Locale</code>s by omitting the final component
2714          * up to language, then append candidates generated from the
2715          * <code>Locale</code> with country and variant restored:
2716          *
2717          * <ul>
2718          * <li> [<em>L</em>, <em>S</em>, <em>C</em>, <em>V</em>]</li>
2719          * <li> [<em>L</em>, <em>S</em>, <em>C</em>]</li>
2720          * <li> [<em>L</em>, <em>S</em>]</li>
2721          * <li> [<em>L</em>, <em>C</em>, <em>V</em>]</li>
2722          * <li> [<em>L</em>, <em>C</em>]</li>
2723          * <li> [<em>L</em>]</li>
2724          * <li> <code>Locale.ROOT</code></li>
2725          * </ul></li>
2726          *
2727          * <li>For an input <code>Locale</code> with a variant value consisting
2728          * of multiple subtags separated by underscore, generate candidate
2729          * <code>Locale</code>s by omitting the variant subtags one by one, then
2730          * insert them after every occurrence of <code> Locale</code>s with the
2731          * full variant value in the original list.  For example, if the
2732          * the variant consists of two subtags <em>V1</em> and <em>V2</em>:
2733          *
2734          * <ul>
2735          * <li> [<em>L</em>, <em>S</em>, <em>C</em>, <em>V1</em>, <em>V2</em>]</li>
2736          * <li> [<em>L</em>, <em>S</em>, <em>C</em>, <em>V1</em>]</li>
2737          * <li> [<em>L</em>, <em>S</em>, <em>C</em>]</li>
2738          * <li> [<em>L</em>, <em>S</em>]</li>
2739          * <li> [<em>L</em>, <em>C</em>, <em>V1</em>, <em>V2</em>]</li>
2740          * <li> [<em>L</em>, <em>C</em>, <em>V1</em>]</li>
2741          * <li> [<em>L</em>, <em>C</em>]</li>
2742          * <li> [<em>L</em>]</li>
2743          * <li> <code>Locale.ROOT</code></li>
2744          * </ul></li>
2745          *
2746          * <li>Special cases for Chinese.  When an input <code>Locale</code> has the
2747          * language "zh" (Chinese) and an empty script value, either "Hans" (Simplified) or
2748          * "Hant" (Traditional) might be supplied, depending on the country.
2749          * When the country is "CN" (China) or "SG" (Singapore), "Hans" is supplied.
2750          * When the country is "HK" (Hong Kong SAR China), "MO" (Macau SAR China),
2751          * or "TW" (Taiwan), "Hant" is supplied.  For all other countries or when the country
2752          * is empty, no script is supplied.  For example, for <code>Locale("zh", "CN")
2753          * </code>, the candidate list will be:
2754          * <ul>
2755          * <li> [<em>L</em>("zh"), <em>S</em>("Hans"), <em>C</em>("CN")]</li>
2756          * <li> [<em>L</em>("zh"), <em>S</em>("Hans")]</li>
2757          * <li> [<em>L</em>("zh"), <em>C</em>("CN")]</li>
2758          * <li> [<em>L</em>("zh")]</li>
2759          * <li> <code>Locale.ROOT</code></li>
2760          * </ul>
2761          *
2762          * For <code>Locale("zh", "TW")</code>, the candidate list will be:
2763          * <ul>
2764          * <li> [<em>L</em>("zh"), <em>S</em>("Hant"), <em>C</em>("TW")]</li>
2765          * <li> [<em>L</em>("zh"), <em>S</em>("Hant")]</li>
2766          * <li> [<em>L</em>("zh"), <em>C</em>("TW")]</li>
2767          * <li> [<em>L</em>("zh")]</li>
2768          * <li> <code>Locale.ROOT</code></li>
2769          * </ul></li>
2770          *
2771          * <li>Special cases for Norwegian.  Both <code>Locale("no", "NO",
2772          * "NY")</code> and <code>Locale("nn", "NO")</code> represent Norwegian
2773          * Nynorsk.  When a locale's language is "nn", the standard candidate
2774          * list is generated up to [<em>L</em>("nn")], and then the following
2775          * candidates are added:
2776          *
2777          * <ul><li> [<em>L</em>("no"), <em>C</em>("NO"), <em>V</em>("NY")]</li>
2778          * <li> [<em>L</em>("no"), <em>C</em>("NO")]</li>
2779          * <li> [<em>L</em>("no")]</li>
2780          * <li> <code>Locale.ROOT</code></li>
2781          * </ul>
2782          *
2783          * If the locale is exactly <code>Locale("no", "NO", "NY")</code>, it is first
2784          * converted to <code>Locale("nn", "NO")</code> and then the above procedure is
2785          * followed.
2786          *
2787          * <p>Also, Java treats the language "no" as a synonym of Norwegian
2788          * Bokmål "nb".  Except for the single case <code>Locale("no",
2789          * "NO", "NY")</code> (handled above), when an input <code>Locale</code>
2790          * has language "no" or "nb", candidate <code>Locale</code>s with
2791          * language code "no" and "nb" are interleaved, first using the
2792          * requested language, then using its synonym. For example,
2793          * <code>Locale("nb", "NO", "POSIX")</code> generates the following
2794          * candidate list:
2795          *
2796          * <ul>
2797          * <li> [<em>L</em>("nb"), <em>C</em>("NO"), <em>V</em>("POSIX")]</li>
2798          * <li> [<em>L</em>("no"), <em>C</em>("NO"), <em>V</em>("POSIX")]</li>
2799          * <li> [<em>L</em>("nb"), <em>C</em>("NO")]</li>
2800          * <li> [<em>L</em>("no"), <em>C</em>("NO")]</li>
2801          * <li> [<em>L</em>("nb")]</li>
2802          * <li> [<em>L</em>("no")]</li>
2803          * <li> <code>Locale.ROOT</code></li>
2804          * </ul>
2805          *
2806          * <code>Locale("no", "NO", "POSIX")</code> would generate the same list
2807          * except that locales with "no" would appear before the corresponding
2808          * locales with "nb".</li>
2809          * </ol>
2810          *
2811          * <p>The default implementation uses an {@link ArrayList} that
2812          * overriding implementations may modify before returning it to the
2813          * caller. However, a subclass must not modify it after it has
2814          * been returned by <code>getCandidateLocales</code>.
2815          *
2816          * <p>For example, if the given <code>baseName</code> is "Messages"
2817          * and the given <code>locale</code> is
2818          * <code>Locale("ja",&nbsp;"",&nbsp;"XX")</code>, then a
2819          * <code>List</code> of <code>Locale</code>s:
2820          * <pre>
2821          *     Locale("ja", "", "XX")
2822          *     Locale("ja")
2823          *     Locale.ROOT
2824          * </pre>
2825          * is returned. And if the resource bundles for the "ja" and
2826          * "" <code>Locale</code>s are found, then the runtime resource
2827          * lookup path (parent chain) is:
2828          * <pre>{@code
2829          *     Messages_ja -> Messages
2830          * }</pre>
2831          *
2832          * @param baseName
2833          *        the base name of the resource bundle, a fully
2834          *        qualified class name
2835          * @param locale
2836          *        the locale for which a resource bundle is desired
2837          * @return a <code>List</code> of candidate
2838          *        <code>Locale</code>s for the given <code>locale</code>
2839          * @exception NullPointerException
2840          *        if <code>baseName</code> or <code>locale</code> is
2841          *        <code>null</code>
2842          */
2843         public List<Locale> getCandidateLocales(String baseName, Locale locale) {
2844             if (baseName == null) {
2845                 throw new NullPointerException();
2846             }
2847             return new ArrayList<>(CANDIDATES_CACHE.get(locale.getBaseLocale()));
2848         }
2849 
2850         private static final CandidateListCache CANDIDATES_CACHE = new CandidateListCache();
2851 
2852         private static class CandidateListCache extends LocaleObjectCache<BaseLocale, List<Locale>> {
2853             protected List<Locale> createObject(BaseLocale base) {
2854                 String language = base.getLanguage();
2855                 String script = base.getScript();
2856                 String region = base.getRegion();
2857                 String variant = base.getVariant();
2858 
2859                 // Special handling for Norwegian
2860                 boolean isNorwegianBokmal = false;
2861                 boolean isNorwegianNynorsk = false;
2862                 if (language.equals("no")) {
2863                     if (region.equals("NO") && variant.equals("NY")) {
2864                         variant = "";
2865                         isNorwegianNynorsk = true;
2866                     } else {
2867                         isNorwegianBokmal = true;
2868                     }
2869                 }
2870                 if (language.equals("nb") || isNorwegianBokmal) {
2871                     List<Locale> tmpList = getDefaultList("nb", script, region, variant);
2872                     // Insert a locale replacing "nb" with "no" for every list entry
2873                     List<Locale> bokmalList = new LinkedList<>();
2874                     for (Locale l : tmpList) {
2875                         bokmalList.add(l);
2876                         if (l.getLanguage().length() == 0) {
2877                             break;
2878                         }
2879                         bokmalList.add(Locale.getInstance("no", l.getScript(), l.getCountry(),
2880                                 l.getVariant(), null));
2881                     }
2882                     return bokmalList;
2883                 } else if (language.equals("nn") || isNorwegianNynorsk) {
2884                     // Insert no_NO_NY, no_NO, no after nn
2885                     List<Locale> nynorskList = getDefaultList("nn", script, region, variant);
2886                     int idx = nynorskList.size() - 1;
2887                     nynorskList.add(idx++, Locale.getInstance("no", "NO", "NY"));
2888                     nynorskList.add(idx++, Locale.getInstance("no", "NO", ""));
2889                     nynorskList.add(idx++, Locale.getInstance("no", "", ""));
2890                     return nynorskList;
2891                 }
2892                 // Special handling for Chinese
2893                 else if (language.equals("zh")) {
2894                     if (script.length() == 0 && region.length() > 0) {
2895                         // Supply script for users who want to use zh_Hans/zh_Hant
2896                         // as bundle names (recommended for Java7+)
2897                         switch (region) {
2898                         case "TW":
2899                         case "HK":
2900                         case "MO":
2901                             script = "Hant";
2902                             break;
2903                         case "CN":
2904                         case "SG":
2905                             script = "Hans";
2906                             break;
2907                         }
2908                     }
2909                 }
2910 
2911                 return getDefaultList(language, script, region, variant);
2912             }
2913 
2914             private static List<Locale> getDefaultList(String language, String script, String region, String variant) {
2915                 List<String> variants = null;
2916 
2917                 if (variant.length() > 0) {
2918                     variants = new LinkedList<>();
2919                     int idx = variant.length();
2920                     while (idx != -1) {
2921                         variants.add(variant.substring(0, idx));
2922                         idx = variant.lastIndexOf('_', --idx);
2923                     }
2924                 }
2925 
2926                 List<Locale> list = new LinkedList<>();
2927 
2928                 if (variants != null) {
2929                     for (String v : variants) {
2930                         list.add(Locale.getInstance(language, script, region, v, null));
2931                     }
2932                 }
2933                 if (region.length() > 0) {
2934                     list.add(Locale.getInstance(language, script, region, "", null));
2935                 }
2936                 if (script.length() > 0) {
2937                     list.add(Locale.getInstance(language, script, "", "", null));
2938                     // Special handling for Chinese
2939                     if (language.equals("zh")) {
2940                         if (region.length() == 0) {
2941                             // Supply region(country) for users who still package Chinese
2942                             // bundles using old convension.
2943                             switch (script) {
2944                                 case "Hans":
2945                                     region = "CN";
2946                                     break;
2947                                 case "Hant":
2948                                     region = "TW";
2949                                     break;
2950                             }
2951                         }
2952                     }
2953 
2954                     // With script, after truncating variant, region and script,
2955                     // start over without script.
2956                     if (variants != null) {
2957                         for (String v : variants) {
2958                             list.add(Locale.getInstance(language, "", region, v, null));
2959                         }
2960                     }
2961                     if (region.length() > 0) {
2962                         list.add(Locale.getInstance(language, "", region, "", null));
2963                     }
2964                 }
2965                 if (language.length() > 0) {
2966                     list.add(Locale.getInstance(language, "", "", "", null));
2967                 }
2968                 // Add root locale at the end
2969                 list.add(Locale.ROOT);
2970 
2971                 return list;
2972             }
2973         }
2974 
2975         /**
2976          * Returns a <code>Locale</code> to be used as a fallback locale for
2977          * further resource bundle searches by the
2978          * <code>ResourceBundle.getBundle</code> factory method. This method
2979          * is called from the factory method every time when no resulting
2980          * resource bundle has been found for <code>baseName</code> and
2981          * <code>locale</code>, where locale is either the parameter for
2982          * <code>ResourceBundle.getBundle</code> or the previous fallback
2983          * locale returned by this method.
2984          *
2985          * <p>The method returns <code>null</code> if no further fallback
2986          * search is desired.
2987          *
2988          * <p>The default implementation returns the {@linkplain
2989          * Locale#getDefault() default <code>Locale</code>} if the given
2990          * <code>locale</code> isn't the default one.  Otherwise,
2991          * <code>null</code> is returned.
2992          *
2993          * @param baseName
2994          *        the base name of the resource bundle, a fully
2995          *        qualified class name for which
2996          *        <code>ResourceBundle.getBundle</code> has been
2997          *        unable to find any resource bundles (except for the
2998          *        base bundle)
2999          * @param locale
3000          *        the <code>Locale</code> for which
3001          *        <code>ResourceBundle.getBundle</code> has been
3002          *        unable to find any resource bundles (except for the
3003          *        base bundle)
3004          * @return a <code>Locale</code> for the fallback search,
3005          *        or <code>null</code> if no further fallback search
3006          *        is desired.
3007          * @exception NullPointerException
3008          *        if <code>baseName</code> or <code>locale</code>
3009          *        is <code>null</code>
3010          */
3011         public Locale getFallbackLocale(String baseName, Locale locale) {
3012             if (baseName == null) {
3013                 throw new NullPointerException();
3014             }
3015             Locale defaultLocale = Locale.getDefault();
3016             return locale.equals(defaultLocale) ? null : defaultLocale;
3017         }
3018 
3019         /**
3020          * Instantiates a resource bundle for the given bundle name of the
3021          * given format and locale, using the given class loader if
3022          * necessary. This method returns <code>null</code> if there is no
3023          * resource bundle available for the given parameters. If a resource
3024          * bundle can't be instantiated due to an unexpected error, the
3025          * error must be reported by throwing an <code>Error</code> or
3026          * <code>Exception</code> rather than simply returning
3027          * <code>null</code>.
3028          *
3029          * <p>If the <code>reload</code> flag is <code>true</code>, it
3030          * indicates that this method is being called because the previously
3031          * loaded resource bundle has expired.
3032          *
3033          * @implSpec
3034          *
3035          * Resource bundles in named modules are subject to the encapsulation
3036          * rules specified by {@link Module#getResourceAsStream Module.getResourceAsStream}.
3037          * A resource bundle in a named module visible to the given class loader
3038          * is accessible when the package of the resource file corresponding
3039          * to the resource bundle is open unconditionally.
3040          *
3041          * <p>The default implementation instantiates a
3042          * <code>ResourceBundle</code> as follows.
3043          *
3044          * <ul>
3045          *
3046          * <li>The bundle name is obtained by calling {@link
3047          * #toBundleName(String, Locale) toBundleName(baseName,
3048          * locale)}.</li>
3049          *
3050          * <li>If <code>format</code> is <code>"java.class"</code>, the
3051          * {@link Class} specified by the bundle name is loaded with the
3052          * given class loader. If the {@code Class} is found and accessible
3053          * then the <code>ResourceBundle</code> is instantiated.  The
3054          * resource bundle is accessible if the package of the bundle class file
3055          * is open unconditionally; otherwise, {@code IllegalAccessException}
3056          * will be thrown.
3057          * Note that the <code>reload</code> flag is ignored for loading
3058          * class-based resource bundles in this default implementation.
3059          * </li>
3060          *
3061          * <li>If <code>format</code> is <code>"java.properties"</code>,
3062          * {@link #toResourceName(String, String) toResourceName(bundlename,
3063          * "properties")} is called to get the resource name.
3064          * If <code>reload</code> is <code>true</code>, {@link
3065          * ClassLoader#getResource(String) load.getResource} is called
3066          * to get a {@link URL} for creating a {@link
3067          * URLConnection}. This <code>URLConnection</code> is used to
3068          * {@linkplain URLConnection#setUseCaches(boolean) disable the
3069          * caches} of the underlying resource loading layers,
3070          * and to {@linkplain URLConnection#getInputStream() get an
3071          * <code>InputStream</code>}.
3072          * Otherwise, {@link ClassLoader#getResourceAsStream(String)
3073          * loader.getResourceAsStream} is called to get an {@link
3074          * InputStream}. Then, a {@link
3075          * PropertyResourceBundle} is constructed with the
3076          * <code>InputStream</code>.</li>
3077          *
3078          * <li>If <code>format</code> is neither <code>"java.class"</code>
3079          * nor <code>"java.properties"</code>, an
3080          * <code>IllegalArgumentException</code> is thrown.</li>
3081          *
3082          * </ul>
3083          *
3084          * @param baseName
3085          *        the base bundle name of the resource bundle, a fully
3086          *        qualified class name
3087          * @param locale
3088          *        the locale for which the resource bundle should be
3089          *        instantiated
3090          * @param format
3091          *        the resource bundle format to be loaded
3092          * @param loader
3093          *        the <code>ClassLoader</code> to use to load the bundle
3094          * @param reload
3095          *        the flag to indicate bundle reloading; <code>true</code>
3096          *        if reloading an expired resource bundle,
3097          *        <code>false</code> otherwise
3098          * @return the resource bundle instance,
3099          *        or <code>null</code> if none could be found.
3100          * @exception NullPointerException
3101          *        if <code>bundleName</code>, <code>locale</code>,
3102          *        <code>format</code>, or <code>loader</code> is
3103          *        <code>null</code>, or if <code>null</code> is returned by
3104          *        {@link #toBundleName(String, Locale) toBundleName}
3105          * @exception IllegalArgumentException
3106          *        if <code>format</code> is unknown, or if the resource
3107          *        found for the given parameters contains malformed data.
3108          * @exception ClassCastException
3109          *        if the loaded class cannot be cast to <code>ResourceBundle</code>
3110          * @exception IllegalAccessException
3111          *        if the class or its nullary constructor is not
3112          *        accessible.
3113          * @exception InstantiationException
3114          *        if the instantiation of a class fails for some other
3115          *        reason.
3116          * @exception ExceptionInInitializerError
3117          *        if the initialization provoked by this method fails.
3118          * @exception SecurityException
3119          *        If a security manager is present and creation of new
3120          *        instances is denied. See {@link Class#newInstance()}
3121          *        for details.
3122          * @exception IOException
3123          *        if an error occurred when reading resources using
3124          *        any I/O operations
3125          * @see java.util.spi.ResourceBundleProvider#getBundle(String, Locale)
3126          * @revised 9
3127          * @spec JPMS
3128          */
3129         public ResourceBundle newBundle(String baseName, Locale locale, String format,
3130                                         ClassLoader loader, boolean reload)
3131                     throws IllegalAccessException, InstantiationException, IOException {
3132             /*
3133              * Legacy mechanism to locate resource bundle in unnamed module only
3134              * that is visible to the given loader and accessible to the given caller.
3135              */
3136             String bundleName = toBundleName(baseName, locale);
3137             ResourceBundle bundle = null;
3138             if (format.equals("java.class")) {
3139                 try {
3140                     Class<?> c = loader.loadClass(bundleName);
3141                     // If the class isn't a ResourceBundle subclass, throw a
3142                     // ClassCastException.
3143                     if (ResourceBundle.class.isAssignableFrom(c)) {
3144                         @SuppressWarnings("unchecked")
3145                         Class<ResourceBundle> bundleClass = (Class<ResourceBundle>)c;
3146                         Module m = bundleClass.getModule();
3147 
3148                         // To access a resource bundle in a named module,
3149                         // either class-based or properties-based, the resource
3150                         // bundle must be opened unconditionally,
3151                         // same rule as accessing a resource file.
3152                         if (m.isNamed() && !m.isOpen(bundleClass.getPackageName())) {
3153                             throw new IllegalAccessException("unnamed module can't load " +
3154                                 bundleClass.getName() + " in " + m.toString());
3155                         }
3156                         try {
3157                             // bundle in a unnamed module
3158                             Constructor<ResourceBundle> ctor = bundleClass.getConstructor();
3159                             if (!Modifier.isPublic(ctor.getModifiers())) {
3160                                 return null;
3161                             }
3162 
3163                             // java.base may not be able to read the bundleClass's module.
3164                             PrivilegedAction<Void> pa1 = () -> { ctor.setAccessible(true); return null; };
3165                             AccessController.doPrivileged(pa1);
3166                             bundle = ctor.newInstance((Object[]) null);
3167                         } catch (InvocationTargetException e) {
3168                             uncheckedThrow(e);
3169                         }
3170                     } else {
3171                         throw new ClassCastException(c.getName()
3172                                 + " cannot be cast to ResourceBundle");
3173                     }
3174                 } catch (ClassNotFoundException|NoSuchMethodException e) {
3175                 }
3176             } else if (format.equals("java.properties")) {
3177                 final String resourceName = toResourceName0(bundleName, "properties");
3178                 if (resourceName == null) {
3179                     return bundle;
3180                 }
3181 
3182                 final boolean reloadFlag = reload;
3183                 InputStream stream = null;
3184                 try {
3185                     stream = AccessController.doPrivileged(
3186                         new PrivilegedExceptionAction<>() {
3187                             public InputStream run() throws IOException {
3188                                 URL url = loader.getResource(resourceName);
3189                                 if (url == null) return null;
3190 
3191                                 URLConnection connection = url.openConnection();
3192                                 if (reloadFlag) {
3193                                     // Disable caches to get fresh data for
3194                                     // reloading.
3195                                     connection.setUseCaches(false);
3196                                 }
3197                                 return connection.getInputStream();
3198                             }
3199                         });
3200                 } catch (PrivilegedActionException e) {
3201                     throw (IOException) e.getException();
3202                 }
3203                 if (stream != null) {
3204                     try {
3205                         bundle = new PropertyResourceBundle(stream);
3206                     } finally {
3207                         stream.close();
3208                     }
3209                 }
3210             } else {
3211                 throw new IllegalArgumentException("unknown format: " + format);
3212             }
3213             return bundle;
3214         }
3215 
3216         /**
3217          * Returns the time-to-live (TTL) value for resource bundles that
3218          * are loaded under this
3219          * <code>ResourceBundle.Control</code>. Positive time-to-live values
3220          * specify the number of milliseconds a bundle can remain in the
3221          * cache without being validated against the source data from which
3222          * it was constructed. The value 0 indicates that a bundle must be
3223          * validated each time it is retrieved from the cache. {@link
3224          * #TTL_DONT_CACHE} specifies that loaded resource bundles are not
3225          * put in the cache. {@link #TTL_NO_EXPIRATION_CONTROL} specifies
3226          * that loaded resource bundles are put in the cache with no
3227          * expiration control.
3228          *
3229          * <p>The expiration affects only the bundle loading process by the
3230          * <code>ResourceBundle.getBundle</code> factory method.  That is,
3231          * if the factory method finds a resource bundle in the cache that
3232          * has expired, the factory method calls the {@link
3233          * #needsReload(String, Locale, String, ClassLoader, ResourceBundle,
3234          * long) needsReload} method to determine whether the resource
3235          * bundle needs to be reloaded. If <code>needsReload</code> returns
3236          * <code>true</code>, the cached resource bundle instance is removed
3237          * from the cache. Otherwise, the instance stays in the cache,
3238          * updated with the new TTL value returned by this method.
3239          *
3240          * <p>All cached resource bundles are subject to removal from the
3241          * cache due to memory constraints of the runtime environment.
3242          * Returning a large positive value doesn't mean to lock loaded
3243          * resource bundles in the cache.
3244          *
3245          * <p>The default implementation returns {@link #TTL_NO_EXPIRATION_CONTROL}.
3246          *
3247          * @param baseName
3248          *        the base name of the resource bundle for which the
3249          *        expiration value is specified.
3250          * @param locale
3251          *        the locale of the resource bundle for which the
3252          *        expiration value is specified.
3253          * @return the time (0 or a positive millisecond offset from the
3254          *        cached time) to get loaded bundles expired in the cache,
3255          *        {@link #TTL_NO_EXPIRATION_CONTROL} to disable the
3256          *        expiration control, or {@link #TTL_DONT_CACHE} to disable
3257          *        caching.
3258          * @exception NullPointerException
3259          *        if <code>baseName</code> or <code>locale</code> is
3260          *        <code>null</code>
3261          */
3262         public long getTimeToLive(String baseName, Locale locale) {
3263             if (baseName == null || locale == null) {
3264                 throw new NullPointerException();
3265             }
3266             return TTL_NO_EXPIRATION_CONTROL;
3267         }
3268 
3269         /**
3270          * Determines if the expired <code>bundle</code> in the cache needs
3271          * to be reloaded based on the loading time given by
3272          * <code>loadTime</code> or some other criteria. The method returns
3273          * <code>true</code> if reloading is required; <code>false</code>
3274          * otherwise. <code>loadTime</code> is a millisecond offset since
3275          * the <a href="Calendar.html#Epoch"> <code>Calendar</code>
3276          * Epoch</a>.
3277          *
3278          * <p>
3279          * The calling <code>ResourceBundle.getBundle</code> factory method
3280          * calls this method on the <code>ResourceBundle.Control</code>
3281          * instance used for its current invocation, not on the instance
3282          * used in the invocation that originally loaded the resource
3283          * bundle.
3284          *
3285          * <p>The default implementation compares <code>loadTime</code> and
3286          * the last modified time of the source data of the resource
3287          * bundle. If it's determined that the source data has been modified
3288          * since <code>loadTime</code>, <code>true</code> is
3289          * returned. Otherwise, <code>false</code> is returned. This
3290          * implementation assumes that the given <code>format</code> is the
3291          * same string as its file suffix if it's not one of the default
3292          * formats, <code>"java.class"</code> or
3293          * <code>"java.properties"</code>.
3294          *
3295          * @param baseName
3296          *        the base bundle name of the resource bundle, a
3297          *        fully qualified class name
3298          * @param locale
3299          *        the locale for which the resource bundle
3300          *        should be instantiated
3301          * @param format
3302          *        the resource bundle format to be loaded
3303          * @param loader
3304          *        the <code>ClassLoader</code> to use to load the bundle
3305          * @param bundle
3306          *        the resource bundle instance that has been expired
3307          *        in the cache
3308          * @param loadTime
3309          *        the time when <code>bundle</code> was loaded and put
3310          *        in the cache
3311          * @return <code>true</code> if the expired bundle needs to be
3312          *        reloaded; <code>false</code> otherwise.
3313          * @exception NullPointerException
3314          *        if <code>baseName</code>, <code>locale</code>,
3315          *        <code>format</code>, <code>loader</code>, or
3316          *        <code>bundle</code> is <code>null</code>
3317          */
3318         public boolean needsReload(String baseName, Locale locale,
3319                                    String format, ClassLoader loader,
3320                                    ResourceBundle bundle, long loadTime) {
3321             if (bundle == null) {
3322                 throw new NullPointerException();
3323             }
3324             if (format.equals("java.class") || format.equals("java.properties")) {
3325                 format = format.substring(5);
3326             }
3327             boolean result = false;
3328             try {
3329                 String resourceName = toResourceName0(toBundleName(baseName, locale), format);
3330                 if (resourceName == null) {
3331                     return result;
3332                 }
3333                 URL url = loader.getResource(resourceName);
3334                 if (url != null) {
3335                     long lastModified = 0;
3336                     URLConnection connection = url.openConnection();
3337                     if (connection != null) {
3338                         // disable caches to get the correct data
3339                         connection.setUseCaches(false);
3340                         if (connection instanceof JarURLConnection) {
3341                             JarEntry ent = ((JarURLConnection)connection).getJarEntry();
3342                             if (ent != null) {
3343                                 lastModified = ent.getTime();
3344                                 if (lastModified == -1) {
3345                                     lastModified = 0;
3346                                 }
3347                             }
3348                         } else {
3349                             lastModified = connection.getLastModified();
3350                         }
3351                     }
3352                     result = lastModified >= loadTime;
3353                 }
3354             } catch (NullPointerException npe) {
3355                 throw npe;
3356             } catch (Exception e) {
3357                 // ignore other exceptions
3358             }
3359             return result;
3360         }
3361 
3362         /**
3363          * Converts the given <code>baseName</code> and <code>locale</code>
3364          * to the bundle name. This method is called from the default
3365          * implementation of the {@link #newBundle(String, Locale, String,
3366          * ClassLoader, boolean) newBundle} and {@link #needsReload(String,
3367          * Locale, String, ClassLoader, ResourceBundle, long) needsReload}
3368          * methods.
3369          *
3370          * <p>This implementation returns the following value:
3371          * <pre>
3372          *     baseName + "_" + language + "_" + script + "_" + country + "_" + variant
3373          * </pre>
3374          * where <code>language</code>, <code>script</code>, <code>country</code>,
3375          * and <code>variant</code> are the language, script, country, and variant
3376          * values of <code>locale</code>, respectively. Final component values that
3377          * are empty Strings are omitted along with the preceding '_'.  When the
3378          * script is empty, the script value is omitted along with the preceding '_'.
3379          * If all of the values are empty strings, then <code>baseName</code>
3380          * is returned.
3381          *
3382          * <p>For example, if <code>baseName</code> is
3383          * <code>"baseName"</code> and <code>locale</code> is
3384          * <code>Locale("ja",&nbsp;"",&nbsp;"XX")</code>, then
3385          * <code>"baseName_ja_&thinsp;_XX"</code> is returned. If the given
3386          * locale is <code>Locale("en")</code>, then
3387          * <code>"baseName_en"</code> is returned.
3388          *
3389          * <p>Overriding this method allows applications to use different
3390          * conventions in the organization and packaging of localized
3391          * resources.
3392          *
3393          * @param baseName
3394          *        the base name of the resource bundle, a fully
3395          *        qualified class name
3396          * @param locale
3397          *        the locale for which a resource bundle should be
3398          *        loaded
3399          * @return the bundle name for the resource bundle
3400          * @exception NullPointerException
3401          *        if <code>baseName</code> or <code>locale</code>
3402          *        is <code>null</code>
3403          * @see java.util.spi.AbstractResourceBundleProvider#toBundleName(String, Locale)
3404          */
3405         public String toBundleName(String baseName, Locale locale) {
3406             if (locale == Locale.ROOT) {
3407                 return baseName;
3408             }
3409 
3410             String language = locale.getLanguage();
3411             String script = locale.getScript();
3412             String country = locale.getCountry();
3413             String variant = locale.getVariant();
3414 
3415             if (language == "" && country == "" && variant == "") {
3416                 return baseName;
3417             }
3418 
3419             StringBuilder sb = new StringBuilder(baseName);
3420             sb.append('_');
3421             if (script != "") {
3422                 if (variant != "") {
3423                     sb.append(language).append('_').append(script).append('_').append(country).append('_').append(variant);
3424                 } else if (country != "") {
3425                     sb.append(language).append('_').append(script).append('_').append(country);
3426                 } else {
3427                     sb.append(language).append('_').append(script);
3428                 }
3429             } else {
3430                 if (variant != "") {
3431                     sb.append(language).append('_').append(country).append('_').append(variant);
3432                 } else if (country != "") {
3433                     sb.append(language).append('_').append(country);
3434                 } else {
3435                     sb.append(language);
3436                 }
3437             }
3438             return sb.toString();
3439 
3440         }
3441 
3442         /**
3443          * Converts the given <code>bundleName</code> to the form required
3444          * by the {@link ClassLoader#getResource ClassLoader.getResource}
3445          * method by replacing all occurrences of <code>'.'</code> in
3446          * <code>bundleName</code> with <code>'/'</code> and appending a
3447          * <code>'.'</code> and the given file <code>suffix</code>. For
3448          * example, if <code>bundleName</code> is
3449          * <code>"foo.bar.MyResources_ja_JP"</code> and <code>suffix</code>
3450          * is <code>"properties"</code>, then
3451          * <code>"foo/bar/MyResources_ja_JP.properties"</code> is returned.
3452          *
3453          * @param bundleName
3454          *        the bundle name
3455          * @param suffix
3456          *        the file type suffix
3457          * @return the converted resource name
3458          * @exception NullPointerException
3459          *         if <code>bundleName</code> or <code>suffix</code>
3460          *         is <code>null</code>
3461          */
3462         public final String toResourceName(String bundleName, String suffix) {
3463             StringBuilder sb = new StringBuilder(bundleName.length() + 1 + suffix.length());
3464             sb.append(bundleName.replace('.', '/')).append('.').append(suffix);
3465             return sb.toString();
3466         }
3467 
3468         private String toResourceName0(String bundleName, String suffix) {
3469             // application protocol check
3470             if (bundleName.contains("://")) {
3471                 return null;
3472             } else {
3473                 return toResourceName(bundleName, suffix);
3474             }
3475         }
3476     }
3477 
3478     @SuppressWarnings("unchecked")
3479     private static <T extends Throwable> void uncheckedThrow(Throwable t) throws T {
3480         if (t != null)
3481             throw (T)t;
3482         else
3483             throw new Error("Unknown Exception");
3484     }
3485 
3486     private static class SingleFormatControl extends Control {
3487         private static final Control PROPERTIES_ONLY
3488             = new SingleFormatControl(FORMAT_PROPERTIES);
3489 
3490         private static final Control CLASS_ONLY
3491             = new SingleFormatControl(FORMAT_CLASS);
3492 
3493         private final List<String> formats;
3494 
3495         protected SingleFormatControl(List<String> formats) {
3496             this.formats = formats;
3497         }
3498 
3499         public List<String> getFormats(String baseName) {
3500             if (baseName == null) {
3501                 throw new NullPointerException();
3502             }
3503             return formats;
3504         }
3505     }
3506 
3507     private static final class NoFallbackControl extends SingleFormatControl {
3508         private static final Control NO_FALLBACK
3509             = new NoFallbackControl(FORMAT_DEFAULT);
3510 
3511         private static final Control PROPERTIES_ONLY_NO_FALLBACK
3512             = new NoFallbackControl(FORMAT_PROPERTIES);
3513 
3514         private static final Control CLASS_ONLY_NO_FALLBACK
3515             = new NoFallbackControl(FORMAT_CLASS);
3516 
3517         protected NoFallbackControl(List<String> formats) {
3518             super(formats);
3519         }
3520 
3521         public Locale getFallbackLocale(String baseName, Locale locale) {
3522             if (baseName == null || locale == null) {
3523                 throw new NullPointerException();
3524             }
3525             return null;
3526         }
3527     }
3528 
3529     private static class ResourceBundleProviderHelper {
3530         /**
3531          * Returns a new ResourceBundle instance of the given bundleClass
3532          */
3533         static ResourceBundle newResourceBundle(Class<? extends ResourceBundle> bundleClass) {
3534             try {
3535                 @SuppressWarnings("unchecked")
3536                 Constructor<? extends ResourceBundle> ctor =
3537                     bundleClass.getConstructor();
3538                 if (!Modifier.isPublic(ctor.getModifiers())) {
3539                     return null;
3540                 }
3541                 // java.base may not be able to read the bundleClass's module.
3542                 PrivilegedAction<Void> pa = () -> { ctor.setAccessible(true); return null;};
3543                 AccessController.doPrivileged(pa);
3544                 try {
3545                     return ctor.newInstance((Object[]) null);
3546                 } catch (InvocationTargetException e) {
3547                     uncheckedThrow(e);
3548                 } catch (InstantiationException | IllegalAccessException e) {
3549                     throw new InternalError(e);
3550                 }
3551             } catch (NoSuchMethodException e) {
3552                 throw new InternalError(e);
3553             }
3554             return null;
3555         }
3556 
3557         /**
3558          * Loads a {@code ResourceBundle} of the given {@code bundleName} local to
3559          * the given {@code module}. If not found, search the bundle class
3560          * that is visible from the module's class loader.
3561          *
3562          * The caller module is used for access check only.
3563          */
3564         static ResourceBundle loadResourceBundle(Module callerModule,
3565                                                  Module module,
3566                                                  String baseName,
3567                                                  Locale locale)
3568         {
3569             String bundleName = Control.INSTANCE.toBundleName(baseName, locale);
3570             try {
3571                 PrivilegedAction<Class<?>> pa = () -> Class.forName(module, bundleName);
3572                 Class<?> c = AccessController.doPrivileged(pa, null, GET_CLASSLOADER_PERMISSION);
3573                 trace("local in %s %s caller %s: %s%n", module, bundleName, callerModule, c);
3574 
3575                 if (c == null) {
3576                     // if not found from the given module, locate resource bundle
3577                     // that is visible to the module's class loader
3578                     ClassLoader loader = getLoader(module);
3579                     if (loader != null) {
3580                         c = Class.forName(bundleName, false, loader);
3581                     } else {
3582                         c = BootLoader.loadClassOrNull(bundleName);
3583                     }
3584                     trace("loader for %s %s caller %s: %s%n", module, bundleName, callerModule, c);
3585                 }
3586 
3587                 if (c != null && ResourceBundle.class.isAssignableFrom(c)) {
3588                     @SuppressWarnings("unchecked")
3589                     Class<ResourceBundle> bundleClass = (Class<ResourceBundle>) c;
3590                     Module m = bundleClass.getModule();
3591                     if (!isAccessible(callerModule, m, bundleClass.getPackageName())) {
3592                         trace("   %s does not have access to %s/%s%n", callerModule,
3593                               m.getName(), bundleClass.getPackageName());
3594                         return null;
3595                     }
3596 
3597                     return newResourceBundle(bundleClass);
3598                 }
3599             } catch (ClassNotFoundException e) {}
3600             return null;
3601         }
3602 
3603         /**
3604          * Tests if resources of the given package name from the given module are
3605          * open to the caller module.
3606          */
3607         static boolean isAccessible(Module callerModule, Module module, String pn) {
3608             if (!module.isNamed() || callerModule == module)
3609                 return true;
3610 
3611             return module.isOpen(pn, callerModule);
3612         }
3613 
3614         /**
3615          * Loads properties of the given {@code bundleName} local in the given
3616          * {@code module}.  If the .properties is not found or not open
3617          * to the caller module to access, it will find the resource that
3618          * is visible to the module's class loader.
3619          *
3620          * The caller module is used for access check only.
3621          */
3622         static ResourceBundle loadPropertyResourceBundle(Module callerModule,
3623                                                          Module module,
3624                                                          String baseName,
3625                                                          Locale locale)
3626             throws IOException
3627         {
3628             String bundleName = Control.INSTANCE.toBundleName(baseName, locale);
3629 
3630             PrivilegedAction<InputStream> pa = () -> {
3631                 try {
3632                     String resourceName = Control.INSTANCE
3633                         .toResourceName0(bundleName, "properties");
3634                     if (resourceName == null) {
3635                         return null;
3636                     }
3637                     trace("local in %s %s caller %s%n", module, resourceName, callerModule);
3638 
3639                     // if the package is in the given module but not opened
3640                     // locate it from the given module first.
3641                     String pn = toPackageName(bundleName);
3642                     trace("   %s/%s is accessible to %s : %s%n",
3643                             module.getName(), pn, callerModule,
3644                             isAccessible(callerModule, module, pn));
3645                     if (isAccessible(callerModule, module, pn)) {
3646                         InputStream in = module.getResourceAsStream(resourceName);
3647                         if (in != null) {
3648                             return in;
3649                         }
3650                     }
3651 
3652                     ClassLoader loader = module.getClassLoader();
3653                     trace("loader for %s %s caller %s%n", module, resourceName, callerModule);
3654 
3655                     try {
3656                         if (loader != null) {
3657                             return loader.getResourceAsStream(resourceName);
3658                         } else {
3659                             URL url = BootLoader.findResource(resourceName);
3660                             if (url != null) {
3661                                 return url.openStream();
3662                             }
3663                         }
3664                     } catch (Exception e) {}
3665                     return null;
3666 
3667                 } catch (IOException e) {
3668                     throw new UncheckedIOException(e);
3669                 }
3670             };
3671 
3672             try (InputStream stream = AccessController.doPrivileged(pa)) {
3673                 if (stream != null) {
3674                     return new PropertyResourceBundle(stream);
3675                 } else {
3676                     return null;
3677                 }
3678             } catch (UncheckedIOException e) {
3679                 throw e.getCause();
3680             }
3681         }
3682 
3683         private static String toPackageName(String bundleName) {
3684             int i = bundleName.lastIndexOf('.');
3685             return i != -1 ? bundleName.substring(0, i) : "";
3686         }
3687 
3688     }
3689 
3690     private static final boolean TRACE_ON = Boolean.valueOf(
3691         GetPropertyAction.privilegedGetProperty("resource.bundle.debug", "false"));
3692 
3693     private static void trace(String format, Object... params) {
3694         if (TRACE_ON)
3695             System.out.format(format, params);
3696     }
3697 }