1 /*
2 * Copyright (c) 2013, 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 package java.lang;
27
28 import java.io.InputStream;
29 import java.io.IOException;
30 import java.io.UncheckedIOException;
31 import java.io.File;
32 import java.lang.reflect.Constructor;
33 import java.net.URL;
34 import java.security.AccessController;
35 import java.security.AccessControlContext;
36 import java.security.CodeSource;
37 import java.security.PrivilegedAction;
38 import java.security.ProtectionDomain;
39 import java.security.cert.Certificate;
40 import java.util.Arrays;
41 import java.util.Collections;
42 import java.util.Deque;
43 import java.util.Enumeration;
44 import java.util.HashMap;
45 import java.util.HashSet;
46 import java.util.Hashtable;
47 import java.util.LinkedList;
48 import java.util.Map;
49 import java.util.NoSuchElementException;
50 import java.util.Objects;
51 import java.util.Set;
52 import java.util.Spliterator;
53 import java.util.Spliterators;
54 import java.util.Vector;
55 import java.util.WeakHashMap;
56 import java.util.concurrent.ConcurrentHashMap;
57 import java.util.function.Supplier;
58 import java.util.stream.Stream;
59 import java.util.stream.StreamSupport;
60
61 import jdk.internal.perf.PerfCounter;
62 import jdk.internal.loader.BootLoader;
63 import jdk.internal.loader.ClassLoaders;
64 import jdk.internal.misc.Unsafe;
65 import jdk.internal.misc.VM;
66 import jdk.internal.ref.CleanerFactory;
67 import jdk.internal.reflect.CallerSensitive;
68 import jdk.internal.reflect.Reflection;
69 import sun.reflect.misc.ReflectUtil;
70 import sun.security.util.SecurityConstants;
71
72 /**
73 * A class loader is an object that is responsible for loading classes. The
74 * class {@code ClassLoader} is an abstract class. Given the <a
75 * href="#name">binary name</a> of a class, a class loader should attempt to
76 * locate or generate data that constitutes a definition for the class. A
77 * typical strategy is to transform the name into a file name and then read a
78 * "class file" of that name from a file system.
79 *
80 * <p> Every {@link java.lang.Class Class} object contains a {@link
81 * Class#getClassLoader() reference} to the {@code ClassLoader} that defined
82 * it.
83 *
84 * <p> {@code Class} objects for array classes are not created by class
85 * loaders, but are created automatically as required by the Java runtime.
86 * The class loader for an array class, as returned by {@link
87 * Class#getClassLoader()} is the same as the class loader for its element
88 * type; if the element type is a primitive type, then the array class has no
89 * class loader.
90 *
91 * <p> Applications implement subclasses of {@code ClassLoader} in order to
92 * extend the manner in which the Java virtual machine dynamically loads
93 * classes.
94 *
95 * <p> Class loaders may typically be used by security managers to indicate
96 * security domains.
97 *
98 * <p> In addition to loading classes, a class loader is also responsible for
99 * locating resources. A resource is some data (a "{@code .class}" file,
100 * configuration data, or an image for example) that is identified with an
101 * abstract '/'-separated path name. Resources are typically packaged with an
102 * application or library so that they can be located by code in the
103 * application or library. In some cases, the resources are included so that
104 * they can be located by other libraries.
105 *
106 * <p> The {@code ClassLoader} class uses a delegation model to search for
107 * classes and resources. Each instance of {@code ClassLoader} has an
108 * associated parent class loader. When requested to find a class or
109 * resource, a {@code ClassLoader} instance will usually delegate the search
110 * for the class or resource to its parent class loader before attempting to
111 * find the class or resource itself.
112 *
113 * <p> Class loaders that support concurrent loading of classes are known as
114 * <em>{@linkplain #isRegisteredAsParallelCapable() parallel capable}</em> class
115 * loaders and are required to register themselves at their class initialization
116 * time by invoking the {@link
117 * #registerAsParallelCapable ClassLoader.registerAsParallelCapable}
118 * method. Note that the {@code ClassLoader} class is registered as parallel
119 * capable by default. However, its subclasses still need to register themselves
120 * if they are parallel capable.
121 * In environments in which the delegation model is not strictly
122 * hierarchical, class loaders need to be parallel capable, otherwise class
123 * loading can lead to deadlocks because the loader lock is held for the
124 * duration of the class loading process (see {@link #loadClass
125 * loadClass} methods).
126 *
127 * <h3> <a id="builtinLoaders">Run-time Built-in Class Loaders</a></h3>
128 *
129 * The Java run-time has the following built-in class loaders:
130 *
131 * <ul>
132 * <li><p>Bootstrap class loader.
133 * It is the virtual machine's built-in class loader, typically represented
134 * as {@code null}, and does not have a parent.</li>
135 * <li><p>{@linkplain #getPlatformClassLoader() Platform class loader}.
136 * All <em>platform classes</em> are visible to the platform class loader
137 * that can be used as the parent of a {@code ClassLoader} instance.
138 * Platform classes include Java SE platform APIs, their implementation
139 * classes and JDK-specific run-time classes that are defined by the
140 * platform class loader or its ancestors.
141 * <p> To allow for upgrading/overriding of modules defined to the platform
142 * class loader, and where upgraded modules read modules defined to class
143 * loaders other than the platform class loader and its ancestors, then
144 * the platform class loader may have to delegate to other class loaders,
145 * the application class loader for example.
146 * In other words, classes in named modules defined to class loaders
147 * other than the platform class loader and its ancestors may be visible
148 * to the platform class loader. </li>
149 * <li><p>{@linkplain #getSystemClassLoader() System class loader}.
150 * It is also known as <em>application class loader</em> and is distinct
151 * from the platform class loader.
152 * The system class loader is typically used to define classes on the
153 * application class path, module path, and JDK-specific tools.
154 * The platform class loader is a parent or an ancestor of the system class
155 * loader that all platform classes are visible to it.</li>
156 * </ul>
157 *
158 * <p> Normally, the Java virtual machine loads classes from the local file
159 * system in a platform-dependent manner.
160 * However, some classes may not originate from a file; they may originate
161 * from other sources, such as the network, or they could be constructed by an
162 * application. The method {@link #defineClass(String, byte[], int, int)
163 * defineClass} converts an array of bytes into an instance of class
164 * {@code Class}. Instances of this newly defined class can be created using
165 * {@link Class#newInstance Class.newInstance}.
166 *
167 * <p> The methods and constructors of objects created by a class loader may
168 * reference other classes. To determine the class(es) referred to, the Java
169 * virtual machine invokes the {@link #loadClass loadClass} method of
170 * the class loader that originally created the class.
171 *
172 * <p> For example, an application could create a network class loader to
173 * download class files from a server. Sample code might look like:
174 *
175 * <blockquote><pre>
176 * ClassLoader loader = new NetworkClassLoader(host, port);
177 * Object main = loader.loadClass("Main", true).newInstance();
178 * . . .
179 * </pre></blockquote>
180 *
181 * <p> The network class loader subclass must define the methods {@link
182 * #findClass findClass} and {@code loadClassData} to load a class
183 * from the network. Once it has downloaded the bytes that make up the class,
184 * it should use the method {@link #defineClass defineClass} to
185 * create a class instance. A sample implementation is:
186 *
187 * <blockquote><pre>
188 * class NetworkClassLoader extends ClassLoader {
189 * String host;
190 * int port;
191 *
192 * public Class findClass(String name) {
193 * byte[] b = loadClassData(name);
194 * return defineClass(name, b, 0, b.length);
195 * }
196 *
197 * private byte[] loadClassData(String name) {
198 * // load the class data from the connection
199 * . . .
200 * }
201 * }
202 * </pre></blockquote>
203 *
204 * <h3> <a id="name">Binary names</a> </h3>
205 *
206 * <p> Any class name provided as a {@code String} parameter to methods in
207 * {@code ClassLoader} must be a binary name as defined by
208 * <cite>The Java™ Language Specification</cite>.
209 *
210 * <p> Examples of valid class names include:
211 * <blockquote><pre>
212 * "java.lang.String"
213 * "javax.swing.JSpinner$DefaultEditor"
214 * "java.security.KeyStore$Builder$FileBuilder$1"
215 * "java.net.URLClassLoader$3$1"
216 * </pre></blockquote>
217 *
218 * <p> Any package name provided as a {@code String} parameter to methods in
219 * {@code ClassLoader} must be either the empty string (denoting an unnamed package)
220 * or a fully qualified name as defined by
221 * <cite>The Java™ Language Specification</cite>.
222 *
223 * @jls 6.7 Fully Qualified Names
224 * @jls 13.1 The Form of a Binary
225 * @see #resolveClass(Class)
226 * @since 1.0
227 * @revised 9
228 * @spec JPMS
229 */
230 public abstract class ClassLoader {
231
232 private static native void registerNatives();
233 static {
234 registerNatives();
235 }
236
237 // The parent class loader for delegation
238 // Note: VM hardcoded the offset of this field, thus all new fields
239 // must be added *after* it.
240 private final ClassLoader parent;
241
242 // class loader name
243 private final String name;
244
245 // the unnamed module for this ClassLoader
246 private final Module unnamedModule;
247
248 /**
249 * Encapsulates the set of parallel capable loader types.
250 */
251 private static class ParallelLoaders {
252 private ParallelLoaders() {}
253
254 // the set of parallel capable loader types
255 private static final Set<Class<? extends ClassLoader>> loaderTypes =
256 Collections.newSetFromMap(new WeakHashMap<>());
257 static {
258 synchronized (loaderTypes) { loaderTypes.add(ClassLoader.class); }
259 }
260
261 /**
262 * Registers the given class loader type as parallel capable.
263 * Returns {@code true} is successfully registered; {@code false} if
264 * loader's super class is not registered.
265 */
266 static boolean register(Class<? extends ClassLoader> c) {
267 synchronized (loaderTypes) {
268 if (loaderTypes.contains(c.getSuperclass())) {
269 // register the class loader as parallel capable
270 // if and only if all of its super classes are.
271 // Note: given current classloading sequence, if
272 // the immediate super class is parallel capable,
273 // all the super classes higher up must be too.
274 loaderTypes.add(c);
275 return true;
276 } else {
277 return false;
278 }
279 }
280 }
281
282 /**
283 * Returns {@code true} if the given class loader type is
284 * registered as parallel capable.
285 */
286 static boolean isRegistered(Class<? extends ClassLoader> c) {
287 synchronized (loaderTypes) {
288 return loaderTypes.contains(c);
289 }
290 }
291 }
292
293 // Maps class name to the corresponding lock object when the current
294 // class loader is parallel capable.
295 // Note: VM also uses this field to decide if the current class loader
296 // is parallel capable and the appropriate lock object for class loading.
297 private final ConcurrentHashMap<String, Object> parallelLockMap;
298
299 // Maps packages to certs
300 private final Map <String, Certificate[]> package2certs;
301
302 // Shared among all packages with unsigned classes
303 private static final Certificate[] nocerts = new Certificate[0];
304
305 // The classes loaded by this class loader. The only purpose of this table
306 // is to keep the classes from being GC'ed until the loader is GC'ed.
307 private final Vector<Class<?>> classes = new Vector<>();
308
309 // The "default" domain. Set as the default ProtectionDomain on newly
310 // created classes.
311 private final ProtectionDomain defaultDomain =
312 new ProtectionDomain(new CodeSource(null, (Certificate[]) null),
313 null, this, null);
314
315 // Invoked by the VM to record every loaded class with this loader.
316 void addClass(Class<?> c) {
317 classes.addElement(c);
318 }
319
320 // The packages defined in this class loader. Each package name is
321 // mapped to its corresponding NamedPackage object.
322 //
323 // The value is a Package object if ClassLoader::definePackage,
324 // Class::getPackage, ClassLoader::getDefinePackage(s) or
325 // Package::getPackage(s) method is called to define it.
326 // Otherwise, the value is a NamedPackage object.
327 private final ConcurrentHashMap<String, NamedPackage> packages
328 = new ConcurrentHashMap<>();
329
330 /*
331 * Returns a named package for the given module.
332 */
333 private NamedPackage getNamedPackage(String pn, Module m) {
334 NamedPackage p = packages.get(pn);
335 if (p == null) {
336 p = new NamedPackage(pn, m);
337
338 NamedPackage value = packages.putIfAbsent(pn, p);
339 if (value != null) {
340 // Package object already be defined for the named package
341 p = value;
342 // if definePackage is called by this class loader to define
343 // a package in a named module, this will return Package
344 // object of the same name. Package object may contain
345 // unexpected information but it does not impact the runtime.
346 // this assertion may be helpful for troubleshooting
347 assert value.module() == m;
348 }
349 }
350 return p;
351 }
352
353 private static Void checkCreateClassLoader() {
354 return checkCreateClassLoader(null);
355 }
356
357 private static Void checkCreateClassLoader(String name) {
358 if (name != null && name.isEmpty()) {
359 throw new IllegalArgumentException("name must be non-empty or null");
360 }
361
362 SecurityManager security = System.getSecurityManager();
363 if (security != null) {
364 security.checkCreateClassLoader();
365 }
366 return null;
367 }
368
369 private ClassLoader(Void unused, String name, ClassLoader parent) {
370 this.name = name;
371 this.parent = parent;
372 this.unnamedModule = new Module(this);
373 if (ParallelLoaders.isRegistered(this.getClass())) {
374 parallelLockMap = new ConcurrentHashMap<>();
375 package2certs = new ConcurrentHashMap<>();
376 assertionLock = new Object();
377 } else {
378 // no finer-grained lock; lock on the classloader instance
379 parallelLockMap = null;
380 package2certs = new Hashtable<>();
381 assertionLock = this;
382 }
383 }
384
385 /**
386 * Creates a new class loader of the specified name and using the
387 * specified parent class loader for delegation.
388 *
389 * @apiNote If the parent is specified as {@code null} (for the
390 * bootstrap class loader) then there is no guarantee that all platform
391 * classes are visible.
392 *
393 * @param name class loader name; or {@code null} if not named
394 * @param parent the parent class loader
395 *
396 * @throws IllegalArgumentException if the given name is empty.
397 *
398 * @throws SecurityException
399 * If a security manager exists and its
400 * {@link SecurityManager#checkCreateClassLoader()}
401 * method doesn't allow creation of a new class loader.
402 *
403 * @since 9
404 * @spec JPMS
405 */
406 protected ClassLoader(String name, ClassLoader parent) {
407 this(checkCreateClassLoader(name), name, parent);
408 }
409
410 /**
411 * Creates a new class loader using the specified parent class loader for
412 * delegation.
413 *
414 * <p> If there is a security manager, its {@link
415 * SecurityManager#checkCreateClassLoader() checkCreateClassLoader} method
416 * is invoked. This may result in a security exception. </p>
417 *
418 * @apiNote If the parent is specified as {@code null} (for the
419 * bootstrap class loader) then there is no guarantee that all platform
420 * classes are visible.
421 *
422 * @param parent
423 * The parent class loader
424 *
425 * @throws SecurityException
426 * If a security manager exists and its
427 * {@code checkCreateClassLoader} method doesn't allow creation
428 * of a new class loader.
429 *
430 * @since 1.2
431 */
432 protected ClassLoader(ClassLoader parent) {
433 this(checkCreateClassLoader(), null, parent);
434 }
435
436 /**
437 * Creates a new class loader using the {@code ClassLoader} returned by
438 * the method {@link #getSystemClassLoader()
439 * getSystemClassLoader()} as the parent class loader.
440 *
441 * <p> If there is a security manager, its {@link
442 * SecurityManager#checkCreateClassLoader()
443 * checkCreateClassLoader} method is invoked. This may result in
444 * a security exception. </p>
445 *
446 * @throws SecurityException
447 * If a security manager exists and its
448 * {@code checkCreateClassLoader} method doesn't allow creation
449 * of a new class loader.
450 */
451 protected ClassLoader() {
452 this(checkCreateClassLoader(), null, getSystemClassLoader());
453 }
454
455 /**
456 * Returns the name of this class loader or {@code null} if
457 * this class loader is not named.
458 *
459 * @apiNote This method is non-final for compatibility. If this
460 * method is overridden, this method must return the same name
461 * as specified when this class loader was instantiated.
462 *
463 * @return name of this class loader; or {@code null} if
464 * this class loader is not named.
465 *
466 * @since 9
467 * @spec JPMS
468 */
469 public String getName() {
470 return name;
471 }
472
473 // package-private used by StackTraceElement to avoid
474 // calling the overrideable getName method
475 final String name() {
476 return name;
477 }
478
479 // -- Class --
480
481 /**
482 * Loads the class with the specified <a href="#name">binary name</a>.
483 * This method searches for classes in the same manner as the {@link
484 * #loadClass(String, boolean)} method. It is invoked by the Java virtual
485 * machine to resolve class references. Invoking this method is equivalent
486 * to invoking {@link #loadClass(String, boolean) loadClass(name,
487 * false)}.
488 *
489 * @param name
490 * The <a href="#name">binary name</a> of the class
491 *
492 * @return The resulting {@code Class} object
493 *
494 * @throws ClassNotFoundException
495 * If the class was not found
496 */
497 public Class<?> loadClass(String name) throws ClassNotFoundException {
498 return loadClass(name, false);
499 }
500
501 /**
502 * Loads the class with the specified <a href="#name">binary name</a>. The
503 * default implementation of this method searches for classes in the
504 * following order:
505 *
506 * <ol>
507 *
508 * <li><p> Invoke {@link #findLoadedClass(String)} to check if the class
509 * has already been loaded. </p></li>
510 *
511 * <li><p> Invoke the {@link #loadClass(String) loadClass} method
512 * on the parent class loader. If the parent is {@code null} the class
513 * loader built into the virtual machine is used, instead. </p></li>
514 *
515 * <li><p> Invoke the {@link #findClass(String)} method to find the
516 * class. </p></li>
517 *
518 * </ol>
519 *
520 * <p> If the class was found using the above steps, and the
521 * {@code resolve} flag is true, this method will then invoke the {@link
522 * #resolveClass(Class)} method on the resulting {@code Class} object.
523 *
524 * <p> Subclasses of {@code ClassLoader} are encouraged to override {@link
525 * #findClass(String)}, rather than this method. </p>
526 *
527 * <p> Unless overridden, this method synchronizes on the result of
528 * {@link #getClassLoadingLock getClassLoadingLock} method
529 * during the entire class loading process.
530 *
531 * @param name
532 * The <a href="#name">binary name</a> of the class
533 *
534 * @param resolve
535 * If {@code true} then resolve the class
536 *
537 * @return The resulting {@code Class} object
538 *
539 * @throws ClassNotFoundException
540 * If the class could not be found
541 */
542 protected Class<?> loadClass(String name, boolean resolve)
543 throws ClassNotFoundException
544 {
545 synchronized (getClassLoadingLock(name)) {
546 // First, check if the class has already been loaded
547 Class<?> c = findLoadedClass(name);
548 if (c == null) {
549 long t0 = System.nanoTime();
550 try {
551 if (parent != null) {
552 c = parent.loadClass(name, false);
553 } else {
554 c = findBootstrapClassOrNull(name);
555 }
556 } catch (ClassNotFoundException e) {
557 // ClassNotFoundException thrown if class not found
558 // from the non-null parent class loader
559 }
560
561 if (c == null) {
562 // If still not found, then invoke findClass in order
563 // to find the class.
564 long t1 = System.nanoTime();
565 c = findClass(name);
566
567 // this is the defining class loader; record the stats
568 PerfCounter.getParentDelegationTime().addTime(t1 - t0);
569 PerfCounter.getFindClassTime().addElapsedTimeFrom(t1);
570 PerfCounter.getFindClasses().increment();
571 }
572 }
573 if (resolve) {
574 resolveClass(c);
575 }
576 return c;
577 }
578 }
579
580 /**
581 * Loads the class with the specified <a href="#name">binary name</a>
582 * in a module defined to this class loader. This method returns {@code null}
583 * if the class could not be found.
584 *
585 * @apiNote This method does not delegate to the parent class loader.
586 *
587 * @implSpec The default implementation of this method searches for classes
588 * in the following order:
589 *
590 * <ol>
591 * <li>Invoke {@link #findLoadedClass(String)} to check if the class
592 * has already been loaded.</li>
593 * <li>Invoke the {@link #findClass(String, String)} method to find the
594 * class in the given module.</li>
595 * </ol>
596 *
597 * @param module
598 * The module
599 * @param name
600 * The <a href="#name">binary name</a> of the class
601 *
602 * @return The resulting {@code Class} object in a module defined by
603 * this class loader, or {@code null} if the class could not be found.
604 */
605 final Class<?> loadClass(Module module, String name) {
606 synchronized (getClassLoadingLock(name)) {
607 // First, check if the class has already been loaded
608 Class<?> c = findLoadedClass(name);
609 if (c == null) {
610 c = findClass(module.getName(), name);
611 }
612 if (c != null && c.getModule() == module) {
613 return c;
614 } else {
615 return null;
616 }
617 }
618 }
619
620 /**
621 * Returns the lock object for class loading operations.
622 * For backward compatibility, the default implementation of this method
623 * behaves as follows. If this ClassLoader object is registered as
624 * parallel capable, the method returns a dedicated object associated
625 * with the specified class name. Otherwise, the method returns this
626 * ClassLoader object.
627 *
628 * @param className
629 * The name of the to-be-loaded class
630 *
631 * @return the lock for class loading operations
632 *
633 * @throws NullPointerException
634 * If registered as parallel capable and {@code className} is null
635 *
636 * @see #loadClass(String, boolean)
637 *
638 * @since 1.7
639 */
640 protected Object getClassLoadingLock(String className) {
641 Object lock = this;
642 if (parallelLockMap != null) {
643 Object newLock = new Object();
644 lock = parallelLockMap.putIfAbsent(className, newLock);
645 if (lock == null) {
646 lock = newLock;
647 }
648 }
649 return lock;
650 }
651
652 // This method is invoked by the virtual machine to load a class.
653 private Class<?> loadClassInternal(String name)
654 throws ClassNotFoundException
655 {
656 // For backward compatibility, explicitly lock on 'this' when
657 // the current class loader is not parallel capable.
658 if (parallelLockMap == null) {
659 synchronized (this) {
660 return loadClass(name);
661 }
662 } else {
663 return loadClass(name);
664 }
665 }
666
667 // Invoked by the VM after loading class with this loader.
668 private void checkPackageAccess(Class<?> cls, ProtectionDomain pd) {
669 final SecurityManager sm = System.getSecurityManager();
670 if (sm != null) {
671 if (ReflectUtil.isNonPublicProxyClass(cls)) {
672 for (Class<?> intf: cls.getInterfaces()) {
673 checkPackageAccess(intf, pd);
674 }
675 return;
676 }
677
678 final String name = cls.getName();
679 final int i = name.lastIndexOf('.');
680 if (i != -1) {
681 AccessController.doPrivileged(new PrivilegedAction<>() {
682 public Void run() {
683 sm.checkPackageAccess(name.substring(0, i));
684 return null;
685 }
686 }, new AccessControlContext(new ProtectionDomain[] {pd}));
687 }
688 }
689 }
690
691 /**
692 * Finds the class with the specified <a href="#name">binary name</a>.
693 * This method should be overridden by class loader implementations that
694 * follow the delegation model for loading classes, and will be invoked by
695 * the {@link #loadClass loadClass} method after checking the
696 * parent class loader for the requested class.
697 *
698 * @implSpec The default implementation throws {@code ClassNotFoundException}.
699 *
700 * @param name
701 * The <a href="#name">binary name</a> of the class
702 *
703 * @return The resulting {@code Class} object
704 *
705 * @throws ClassNotFoundException
706 * If the class could not be found
707 *
708 * @since 1.2
709 */
710 protected Class<?> findClass(String name) throws ClassNotFoundException {
711 throw new ClassNotFoundException(name);
712 }
713
714 /**
715 * Finds the class with the given <a href="#name">binary name</a>
716 * in a module defined to this class loader.
717 * Class loader implementations that support the loading from modules
718 * should override this method.
719 *
720 * @apiNote This method returns {@code null} rather than throwing
721 * {@code ClassNotFoundException} if the class could not be found.
722 *
723 * @implSpec The default implementation attempts to find the class by
724 * invoking {@link #findClass(String)} when the {@code moduleName} is
725 * {@code null}. It otherwise returns {@code null}.
726 *
727 * @param moduleName
728 * The module name; or {@code null} to find the class in the
729 * {@linkplain #getUnnamedModule() unnamed module} for this
730 * class loader
731
732 * @param name
733 * The <a href="#name">binary name</a> of the class
734 *
735 * @return The resulting {@code Class} object, or {@code null}
736 * if the class could not be found.
737 *
738 * @since 9
739 * @spec JPMS
740 */
741 protected Class<?> findClass(String moduleName, String name) {
742 if (moduleName == null) {
743 try {
744 return findClass(name);
745 } catch (ClassNotFoundException ignore) { }
746 }
747 return null;
748 }
749
750
751 /**
752 * Converts an array of bytes into an instance of class {@code Class}.
753 * Before the {@code Class} can be used it must be resolved. This method
754 * is deprecated in favor of the version that takes a <a
755 * href="#name">binary name</a> as its first argument, and is more secure.
756 *
757 * @param b
758 * The bytes that make up the class data. The bytes in positions
759 * {@code off} through {@code off+len-1} should have the format
760 * of a valid class file as defined by
761 * <cite>The Java™ Virtual Machine Specification</cite>.
762 *
763 * @param off
764 * The start offset in {@code b} of the class data
765 *
766 * @param len
767 * The length of the class data
768 *
769 * @return The {@code Class} object that was created from the specified
770 * class data
771 *
772 * @throws ClassFormatError
773 * If the data did not contain a valid class
774 *
775 * @throws IndexOutOfBoundsException
776 * If either {@code off} or {@code len} is negative, or if
777 * {@code off+len} is greater than {@code b.length}.
778 *
779 * @throws SecurityException
780 * If an attempt is made to add this class to a package that
781 * contains classes that were signed by a different set of
782 * certificates than this class, or if an attempt is made
783 * to define a class in a package with a fully-qualified name
784 * that starts with "{@code java.}".
785 *
786 * @see #loadClass(String, boolean)
787 * @see #resolveClass(Class)
788 *
789 * @deprecated Replaced by {@link #defineClass(String, byte[], int, int)
790 * defineClass(String, byte[], int, int)}
791 */
792 @Deprecated(since="1.1")
793 protected final Class<?> defineClass(byte[] b, int off, int len)
794 throws ClassFormatError
795 {
796 return defineClass(null, b, off, len, null);
797 }
798
799 /**
800 * Converts an array of bytes into an instance of class {@code Class}.
801 * Before the {@code Class} can be used it must be resolved.
802 *
803 * <p> This method assigns a default {@link java.security.ProtectionDomain
804 * ProtectionDomain} to the newly defined class. The
805 * {@code ProtectionDomain} is effectively granted the same set of
806 * permissions returned when {@link
807 * java.security.Policy#getPermissions(java.security.CodeSource)
808 * Policy.getPolicy().getPermissions(new CodeSource(null, null))}
809 * is invoked. The default protection domain is created on the first invocation
810 * of {@link #defineClass(String, byte[], int, int) defineClass},
811 * and re-used on subsequent invocations.
812 *
813 * <p> To assign a specific {@code ProtectionDomain} to the class, use
814 * the {@link #defineClass(String, byte[], int, int,
815 * java.security.ProtectionDomain) defineClass} method that takes a
816 * {@code ProtectionDomain} as one of its arguments. </p>
817 *
818 * <p>
819 * This method defines a package in this class loader corresponding to the
820 * package of the {@code Class} (if such a package has not already been defined
821 * in this class loader). The name of the defined package is derived from
822 * the <a href="#name">binary name</a> of the class specified by
823 * the byte array {@code b}.
824 * Other properties of the defined package are as specified by {@link Package}.
825 *
826 * @param name
827 * The expected <a href="#name">binary name</a> of the class, or
828 * {@code null} if not known
829 *
830 * @param b
831 * The bytes that make up the class data. The bytes in positions
832 * {@code off} through {@code off+len-1} should have the format
833 * of a valid class file as defined by
834 * <cite>The Java™ Virtual Machine Specification</cite>.
835 *
836 * @param off
837 * The start offset in {@code b} of the class data
838 *
839 * @param len
840 * The length of the class data
841 *
842 * @return The {@code Class} object that was created from the specified
843 * class data.
844 *
845 * @throws ClassFormatError
846 * If the data did not contain a valid class
847 *
848 * @throws IndexOutOfBoundsException
849 * If either {@code off} or {@code len} is negative, or if
850 * {@code off+len} is greater than {@code b.length}.
851 *
852 * @throws SecurityException
853 * If an attempt is made to add this class to a package that
854 * contains classes that were signed by a different set of
855 * certificates than this class (which is unsigned), or if
856 * {@code name} begins with "{@code java.}".
857 *
858 * @see #loadClass(String, boolean)
859 * @see #resolveClass(Class)
860 * @see java.security.CodeSource
861 * @see java.security.SecureClassLoader
862 *
863 * @since 1.1
864 * @revised 9
865 * @spec JPMS
866 */
867 protected final Class<?> defineClass(String name, byte[] b, int off, int len)
868 throws ClassFormatError
869 {
870 return defineClass(name, b, off, len, null);
871 }
872
873 /* Determine protection domain, and check that:
874 - not define java.* class,
875 - signer of this class matches signers for the rest of the classes in
876 package.
877 */
878 private ProtectionDomain preDefineClass(String name,
879 ProtectionDomain pd)
880 {
881 if (!checkName(name))
882 throw new NoClassDefFoundError("IllegalName: " + name);
883
884 // Note: Checking logic in java.lang.invoke.MemberName.checkForTypeAlias
885 // relies on the fact that spoofing is impossible if a class has a name
886 // of the form "java.*"
887 if ((name != null) && name.startsWith("java.")
888 && this != getBuiltinPlatformClassLoader()) {
889 throw new SecurityException
890 ("Prohibited package name: " +
891 name.substring(0, name.lastIndexOf('.')));
892 }
893 if (pd == null) {
894 pd = defaultDomain;
895 }
896
897 if (name != null) {
898 checkCerts(name, pd.getCodeSource());
899 }
900
901 return pd;
902 }
903
904 private String defineClassSourceLocation(ProtectionDomain pd) {
905 CodeSource cs = pd.getCodeSource();
906 String source = null;
907 if (cs != null && cs.getLocation() != null) {
908 source = cs.getLocation().toString();
909 }
910 return source;
911 }
912
913 private void postDefineClass(Class<?> c, ProtectionDomain pd) {
914 // define a named package, if not present
915 getNamedPackage(c.getPackageName(), c.getModule());
916
917 if (pd.getCodeSource() != null) {
918 Certificate certs[] = pd.getCodeSource().getCertificates();
919 if (certs != null)
920 setSigners(c, certs);
921 }
922 }
923
924 /**
925 * Converts an array of bytes into an instance of class {@code Class},
926 * with a given {@code ProtectionDomain}.
927 *
928 * <p> If the given {@code ProtectionDomain} is {@code null},
929 * then a default protection domain will be assigned to the class as specified
930 * in the documentation for {@link #defineClass(String, byte[], int, int)}.
931 * Before the class can be used it must be resolved.
932 *
933 * <p> The first class defined in a package determines the exact set of
934 * certificates that all subsequent classes defined in that package must
935 * contain. The set of certificates for a class is obtained from the
936 * {@link java.security.CodeSource CodeSource} within the
937 * {@code ProtectionDomain} of the class. Any classes added to that
938 * package must contain the same set of certificates or a
939 * {@code SecurityException} will be thrown. Note that if
940 * {@code name} is {@code null}, this check is not performed.
941 * You should always pass in the <a href="#name">binary name</a> of the
942 * class you are defining as well as the bytes. This ensures that the
943 * class you are defining is indeed the class you think it is.
944 *
945 * <p> If the specified {@code name} begins with "{@code java.}", it can
946 * only be defined by the {@linkplain #getPlatformClassLoader()
947 * platform class loader} or its ancestors; otherwise {@code SecurityException}
948 * will be thrown. If {@code name} is not {@code null}, it must be equal to
949 * the <a href="#name">binary name</a> of the class
950 * specified by the byte array {@code b}, otherwise a {@link
951 * NoClassDefFoundError NoClassDefFoundError} will be thrown.
952 *
953 * <p> This method defines a package in this class loader corresponding to the
954 * package of the {@code Class} (if such a package has not already been defined
955 * in this class loader). The name of the defined package is derived from
956 * the <a href="#name">binary name</a> of the class specified by
957 * the byte array {@code b}.
958 * Other properties of the defined package are as specified by {@link Package}.
959 *
960 * @param name
961 * The expected <a href="#name">binary name</a> of the class, or
962 * {@code null} if not known
963 *
964 * @param b
965 * The bytes that make up the class data. The bytes in positions
966 * {@code off} through {@code off+len-1} should have the format
967 * of a valid class file as defined by
968 * <cite>The Java™ Virtual Machine Specification</cite>.
969 *
970 * @param off
971 * The start offset in {@code b} of the class data
972 *
973 * @param len
974 * The length of the class data
975 *
976 * @param protectionDomain
977 * The {@code ProtectionDomain} of the class
978 *
979 * @return The {@code Class} object created from the data,
980 * and {@code ProtectionDomain}.
981 *
982 * @throws ClassFormatError
983 * If the data did not contain a valid class
984 *
985 * @throws NoClassDefFoundError
986 * If {@code name} is not {@code null} and not equal to the
987 * <a href="#name">binary name</a> of the class specified by {@code b}
988 *
989 * @throws IndexOutOfBoundsException
990 * If either {@code off} or {@code len} is negative, or if
991 * {@code off+len} is greater than {@code b.length}.
992 *
993 * @throws SecurityException
994 * If an attempt is made to add this class to a package that
995 * contains classes that were signed by a different set of
996 * certificates than this class, or if {@code name} begins with
997 * "{@code java.}" and this class loader is not the platform
998 * class loader or its ancestor.
999 *
1000 * @revised 9
1001 * @spec JPMS
1002 */
1003 protected final Class<?> defineClass(String name, byte[] b, int off, int len,
1004 ProtectionDomain protectionDomain)
1005 throws ClassFormatError
1006 {
1007 protectionDomain = preDefineClass(name, protectionDomain);
1008 String source = defineClassSourceLocation(protectionDomain);
1009 Class<?> c = defineClass1(this, name, b, off, len, protectionDomain, source);
1010 postDefineClass(c, protectionDomain);
1011 return c;
1012 }
1013
1014 /**
1015 * Converts a {@link java.nio.ByteBuffer ByteBuffer} into an instance
1016 * of class {@code Class}, with the given {@code ProtectionDomain}.
1017 * If the given {@code ProtectionDomain} is {@code null}, then a default
1018 * protection domain will be assigned to the class as
1019 * specified in the documentation for {@link #defineClass(String, byte[],
1020 * int, int)}. Before the class can be used it must be resolved.
1021 *
1022 * <p>The rules about the first class defined in a package determining the
1023 * set of certificates for the package, the restrictions on class names,
1024 * and the defined package of the class
1025 * are identical to those specified in the documentation for {@link
1026 * #defineClass(String, byte[], int, int, ProtectionDomain)}.
1027 *
1028 * <p> An invocation of this method of the form
1029 * <i>cl</i>{@code .defineClass(}<i>name</i>{@code ,}
1030 * <i>bBuffer</i>{@code ,} <i>pd</i>{@code )} yields exactly the same
1031 * result as the statements
1032 *
1033 *<p> <code>
1034 * ...<br>
1035 * byte[] temp = new byte[bBuffer.{@link
1036 * java.nio.ByteBuffer#remaining remaining}()];<br>
1037 * bBuffer.{@link java.nio.ByteBuffer#get(byte[])
1038 * get}(temp);<br>
1039 * return {@link #defineClass(String, byte[], int, int, ProtectionDomain)
1040 * cl.defineClass}(name, temp, 0,
1041 * temp.length, pd);<br>
1042 * </code></p>
1043 *
1044 * @param name
1045 * The expected <a href="#name">binary name</a>. of the class, or
1046 * {@code null} if not known
1047 *
1048 * @param b
1049 * The bytes that make up the class data. The bytes from positions
1050 * {@code b.position()} through {@code b.position() + b.limit() -1
1051 * } should have the format of a valid class file as defined by
1052 * <cite>The Java™ Virtual Machine Specification</cite>.
1053 *
1054 * @param protectionDomain
1055 * The {@code ProtectionDomain} of the class, or {@code null}.
1056 *
1057 * @return The {@code Class} object created from the data,
1058 * and {@code ProtectionDomain}.
1059 *
1060 * @throws ClassFormatError
1061 * If the data did not contain a valid class.
1062 *
1063 * @throws NoClassDefFoundError
1064 * If {@code name} is not {@code null} and not equal to the
1065 * <a href="#name">binary name</a> of the class specified by {@code b}
1066 *
1067 * @throws SecurityException
1068 * If an attempt is made to add this class to a package that
1069 * contains classes that were signed by a different set of
1070 * certificates than this class, or if {@code name} begins with
1071 * "{@code java.}".
1072 *
1073 * @see #defineClass(String, byte[], int, int, ProtectionDomain)
1074 *
1075 * @since 1.5
1076 * @revised 9
1077 * @spec JPMS
1078 */
1079 protected final Class<?> defineClass(String name, java.nio.ByteBuffer b,
1080 ProtectionDomain protectionDomain)
1081 throws ClassFormatError
1082 {
1083 int len = b.remaining();
1084
1085 // Use byte[] if not a direct ByteBuffer:
1086 if (!b.isDirect()) {
1087 if (b.hasArray()) {
1088 return defineClass(name, b.array(),
1089 b.position() + b.arrayOffset(), len,
1090 protectionDomain);
1091 } else {
1092 // no array, or read-only array
1093 byte[] tb = new byte[len];
1094 b.get(tb); // get bytes out of byte buffer.
1095 return defineClass(name, tb, 0, len, protectionDomain);
1096 }
1097 }
1098
1099 protectionDomain = preDefineClass(name, protectionDomain);
1100 String source = defineClassSourceLocation(protectionDomain);
1101 Class<?> c = defineClass2(this, name, b, b.position(), len, protectionDomain, source);
1102 postDefineClass(c, protectionDomain);
1103 return c;
1104 }
1105
1106 static native Class<?> defineClass1(ClassLoader loader, String name, byte[] b, int off, int len,
1107 ProtectionDomain pd, String source);
1108
1109 static native Class<?> defineClass2(ClassLoader loader, String name, java.nio.ByteBuffer b,
1110 int off, int len, ProtectionDomain pd,
1111 String source);
1112
1113 // true if the name is null or has the potential to be a valid binary name
1114 private boolean checkName(String name) {
1115 if ((name == null) || (name.length() == 0))
1116 return true;
1117 if ((name.indexOf('/') != -1) || (name.charAt(0) == '['))
1118 return false;
1119 return true;
1120 }
1121
1122 private void checkCerts(String name, CodeSource cs) {
1123 int i = name.lastIndexOf('.');
1124 String pname = (i == -1) ? "" : name.substring(0, i);
1125
1126 Certificate[] certs = null;
1127 if (cs != null) {
1128 certs = cs.getCertificates();
1129 }
1130 Certificate[] pcerts = null;
1131 if (parallelLockMap == null) {
1132 synchronized (this) {
1133 pcerts = package2certs.get(pname);
1134 if (pcerts == null) {
1135 package2certs.put(pname, (certs == null? nocerts:certs));
1136 }
1137 }
1138 } else {
1139 pcerts = ((ConcurrentHashMap<String, Certificate[]>)package2certs).
1140 putIfAbsent(pname, (certs == null? nocerts:certs));
1141 }
1142 if (pcerts != null && !compareCerts(pcerts, certs)) {
1143 throw new SecurityException("class \"" + name
1144 + "\"'s signer information does not match signer information"
1145 + " of other classes in the same package");
1146 }
1147 }
1148
1149 /**
1150 * check to make sure the certs for the new class (certs) are the same as
1151 * the certs for the first class inserted in the package (pcerts)
1152 */
1153 private boolean compareCerts(Certificate[] pcerts,
1154 Certificate[] certs)
1155 {
1156 // certs can be null, indicating no certs.
1157 if ((certs == null) || (certs.length == 0)) {
1158 return pcerts.length == 0;
1159 }
1160
1161 // the length must be the same at this point
1162 if (certs.length != pcerts.length)
1163 return false;
1164
1165 // go through and make sure all the certs in one array
1166 // are in the other and vice-versa.
1167 boolean match;
1168 for (Certificate cert : certs) {
1169 match = false;
1170 for (Certificate pcert : pcerts) {
1171 if (cert.equals(pcert)) {
1172 match = true;
1173 break;
1174 }
1175 }
1176 if (!match) return false;
1177 }
1178
1179 // now do the same for pcerts
1180 for (Certificate pcert : pcerts) {
1181 match = false;
1182 for (Certificate cert : certs) {
1183 if (pcert.equals(cert)) {
1184 match = true;
1185 break;
1186 }
1187 }
1188 if (!match) return false;
1189 }
1190
1191 return true;
1192 }
1193
1194 /**
1195 * Links the specified class. This (misleadingly named) method may be
1196 * used by a class loader to link a class. If the class {@code c} has
1197 * already been linked, then this method simply returns. Otherwise, the
1198 * class is linked as described in the "Execution" chapter of
1199 * <cite>The Java™ Language Specification</cite>.
1200 *
1201 * @param c
1202 * The class to link
1203 *
1204 * @throws NullPointerException
1205 * If {@code c} is {@code null}.
1206 *
1207 * @see #defineClass(String, byte[], int, int)
1208 */
1209 protected final void resolveClass(Class<?> c) {
1210 if (c == null) {
1211 throw new NullPointerException();
1212 }
1213 }
1214
1215 /**
1216 * Finds a class with the specified <a href="#name">binary name</a>,
1217 * loading it if necessary.
1218 *
1219 * <p> This method loads the class through the system class loader (see
1220 * {@link #getSystemClassLoader()}). The {@code Class} object returned
1221 * might have more than one {@code ClassLoader} associated with it.
1222 * Subclasses of {@code ClassLoader} need not usually invoke this method,
1223 * because most class loaders need to override just {@link
1224 * #findClass(String)}. </p>
1225 *
1226 * @param name
1227 * The <a href="#name">binary name</a> of the class
1228 *
1229 * @return The {@code Class} object for the specified {@code name}
1230 *
1231 * @throws ClassNotFoundException
1232 * If the class could not be found
1233 *
1234 * @see #ClassLoader(ClassLoader)
1235 * @see #getParent()
1236 */
1237 protected final Class<?> findSystemClass(String name)
1238 throws ClassNotFoundException
1239 {
1240 return getSystemClassLoader().loadClass(name);
1241 }
1242
1243 /**
1244 * Returns a class loaded by the bootstrap class loader;
1245 * or return null if not found.
1246 */
1247 Class<?> findBootstrapClassOrNull(String name) {
1248 if (!checkName(name)) return null;
1249
1250 return findBootstrapClass(name);
1251 }
1252
1253 // return null if not found
1254 private native Class<?> findBootstrapClass(String name);
1255
1256 /**
1257 * Returns the class with the given <a href="#name">binary name</a> if this
1258 * loader has been recorded by the Java virtual machine as an initiating
1259 * loader of a class with that <a href="#name">binary name</a>. Otherwise
1260 * {@code null} is returned.
1261 *
1262 * @param name
1263 * The <a href="#name">binary name</a> of the class
1264 *
1265 * @return The {@code Class} object, or {@code null} if the class has
1266 * not been loaded
1267 *
1268 * @since 1.1
1269 */
1270 protected final Class<?> findLoadedClass(String name) {
1271 if (!checkName(name))
1272 return null;
1273 return findLoadedClass0(name);
1274 }
1275
1276 private final native Class<?> findLoadedClass0(String name);
1277
1278 /**
1279 * Sets the signers of a class. This should be invoked after defining a
1280 * class.
1281 *
1282 * @param c
1283 * The {@code Class} object
1284 *
1285 * @param signers
1286 * The signers for the class
1287 *
1288 * @since 1.1
1289 */
1290 protected final void setSigners(Class<?> c, Object[] signers) {
1291 c.setSigners(signers);
1292 }
1293
1294
1295 // -- Resources --
1296
1297 /**
1298 * Returns a URL to a resource in a module defined to this class loader.
1299 * Class loader implementations that support the loading from modules
1300 * should override this method.
1301 *
1302 * @apiNote This method is the basis for the {@link
1303 * Class#getResource Class.getResource}, {@link Class#getResourceAsStream
1304 * Class.getResourceAsStream}, and {@link Module#getResourceAsStream
1305 * Module.getResourceAsStream} methods. It is not subject to the rules for
1306 * encapsulation specified by {@code Module.getResourceAsStream}.
1307 *
1308 * @implSpec The default implementation attempts to find the resource by
1309 * invoking {@link #findResource(String)} when the {@code moduleName} is
1310 * {@code null}. It otherwise returns {@code null}.
1311 *
1312 * @param moduleName
1313 * The module name; or {@code null} to find a resource in the
1314 * {@linkplain #getUnnamedModule() unnamed module} for this
1315 * class loader
1316 * @param name
1317 * The resource name
1318 *
1319 * @return A URL to the resource; {@code null} if the resource could not be
1320 * found, a URL could not be constructed to locate the resource,
1321 * access to the resource is denied by the security manager, or
1322 * there isn't a module of the given name defined to the class
1323 * loader.
1324 *
1325 * @throws IOException
1326 * If I/O errors occur
1327 *
1328 * @see java.lang.module.ModuleReader#find(String)
1329 * @since 9
1330 * @spec JPMS
1331 */
1332 protected URL findResource(String moduleName, String name) throws IOException {
1333 if (moduleName == null) {
1334 return findResource(name);
1335 } else {
1336 return null;
1337 }
1338 }
1339
1340 /**
1341 * Finds the resource with the given name. A resource is some data
1342 * (images, audio, text, etc) that can be accessed by class code in a way
1343 * that is independent of the location of the code.
1344 *
1345 * <p> The name of a resource is a '{@code /}'-separated path name that
1346 * identifies the resource. </p>
1347 *
1348 * <p> Resources in named modules are subject to the encapsulation rules
1349 * specified by {@link Module#getResourceAsStream Module.getResourceAsStream}.
1350 * Additionally, and except for the special case where the resource has a
1351 * name ending with "{@code .class}", this method will only find resources in
1352 * packages of named modules when the package is {@link Module#isOpen(String)
1353 * opened} unconditionally (even if the caller of this method is in the
1354 * same module as the resource). </p>
1355 *
1356 * @implSpec The default implementation will first search the parent class
1357 * loader for the resource; if the parent is {@code null} the path of the
1358 * class loader built into the virtual machine is searched. If not found,
1359 * this method will invoke {@link #findResource(String)} to find the resource.
1360 *
1361 * @apiNote Where several modules are defined to the same class loader,
1362 * and where more than one module contains a resource with the given name,
1363 * then the ordering that modules are searched is not specified and may be
1364 * very unpredictable.
1365 * When overriding this method it is recommended that an implementation
1366 * ensures that any delegation is consistent with the {@link
1367 * #getResources(java.lang.String) getResources(String)} method.
1368 *
1369 * @param name
1370 * The resource name
1371 *
1372 * @return {@code URL} object for reading the resource; {@code null} if
1373 * the resource could not be found, a {@code URL} could not be
1374 * constructed to locate the resource, the resource is in a package
1375 * that is not opened unconditionally, or access to the resource is
1376 * denied by the security manager.
1377 *
1378 * @throws NullPointerException If {@code name} is {@code null}
1379 *
1380 * @since 1.1
1381 * @revised 9
1382 * @spec JPMS
1383 */
1384 public URL getResource(String name) {
1385 Objects.requireNonNull(name);
1386 URL url;
1387 if (parent != null) {
1388 url = parent.getResource(name);
1389 } else {
1390 url = BootLoader.findResource(name);
1391 }
1392 if (url == null) {
1393 url = findResource(name);
1394 }
1395 return url;
1396 }
1397
1398 /**
1399 * Finds all the resources with the given name. A resource is some data
1400 * (images, audio, text, etc) that can be accessed by class code in a way
1401 * that is independent of the location of the code.
1402 *
1403 * <p> The name of a resource is a {@code /}-separated path name that
1404 * identifies the resource. </p>
1405 *
1406 * <p> Resources in named modules are subject to the encapsulation rules
1407 * specified by {@link Module#getResourceAsStream Module.getResourceAsStream}.
1408 * Additionally, and except for the special case where the resource has a
1409 * name ending with "{@code .class}", this method will only find resources in
1410 * packages of named modules when the package is {@link Module#isOpen(String)
1411 * opened} unconditionally (even if the caller of this method is in the
1412 * same module as the resource). </p>
1413 *
1414 * @implSpec The default implementation will first search the parent class
1415 * loader for the resource; if the parent is {@code null} the path of the
1416 * class loader built into the virtual machine is searched. It then
1417 * invokes {@link #findResources(String)} to find the resources with the
1418 * name in this class loader. It returns an enumeration whose elements
1419 * are the URLs found by searching the parent class loader followed by
1420 * the elements found with {@code findResources}.
1421 *
1422 * @apiNote Where several modules are defined to the same class loader,
1423 * and where more than one module contains a resource with the given name,
1424 * then the ordering is not specified and may be very unpredictable.
1425 * When overriding this method it is recommended that an
1426 * implementation ensures that any delegation is consistent with the {@link
1427 * #getResource(java.lang.String) getResource(String)} method. This should
1428 * ensure that the first element returned by the Enumeration's
1429 * {@code nextElement} method is the same resource that the
1430 * {@code getResource(String)} method would return.
1431 *
1432 * @param name
1433 * The resource name
1434 *
1435 * @return An enumeration of {@link java.net.URL URL} objects for
1436 * the resource. If no resources could be found, the enumeration
1437 * will be empty. Resources for which a {@code URL} cannot be
1438 * constructed, are in package that is not opened unconditionally,
1439 * or access to the resource is denied by the security manager,
1440 * are not returned in the enumeration.
1441 *
1442 * @throws IOException
1443 * If I/O errors occur
1444 * @throws NullPointerException If {@code name} is {@code null}
1445 *
1446 * @since 1.2
1447 * @revised 9
1448 * @spec JPMS
1449 */
1450 public Enumeration<URL> getResources(String name) throws IOException {
1451 Objects.requireNonNull(name);
1452 @SuppressWarnings("unchecked")
1453 Enumeration<URL>[] tmp = (Enumeration<URL>[]) new Enumeration<?>[2];
1454 if (parent != null) {
1455 tmp[0] = parent.getResources(name);
1456 } else {
1457 tmp[0] = BootLoader.findResources(name);
1458 }
1459 tmp[1] = findResources(name);
1460
1461 return new CompoundEnumeration<>(tmp);
1462 }
1463
1464 /**
1465 * Returns a stream whose elements are the URLs of all the resources with
1466 * the given name. A resource is some data (images, audio, text, etc) that
1467 * can be accessed by class code in a way that is independent of the
1468 * location of the code.
1469 *
1470 * <p> The name of a resource is a {@code /}-separated path name that
1471 * identifies the resource.
1472 *
1473 * <p> The resources will be located when the returned stream is evaluated.
1474 * If the evaluation results in an {@code IOException} then the I/O
1475 * exception is wrapped in an {@link UncheckedIOException} that is then
1476 * thrown.
1477 *
1478 * <p> Resources in named modules are subject to the encapsulation rules
1479 * specified by {@link Module#getResourceAsStream Module.getResourceAsStream}.
1480 * Additionally, and except for the special case where the resource has a
1481 * name ending with "{@code .class}", this method will only find resources in
1482 * packages of named modules when the package is {@link Module#isOpen(String)
1483 * opened} unconditionally (even if the caller of this method is in the
1484 * same module as the resource). </p>
1485 *
1486 * @implSpec The default implementation invokes {@link #getResources(String)
1487 * getResources} to find all the resources with the given name and returns
1488 * a stream with the elements in the enumeration as the source.
1489 *
1490 * @apiNote When overriding this method it is recommended that an
1491 * implementation ensures that any delegation is consistent with the {@link
1492 * #getResource(java.lang.String) getResource(String)} method. This should
1493 * ensure that the first element returned by the stream is the same
1494 * resource that the {@code getResource(String)} method would return.
1495 *
1496 * @param name
1497 * The resource name
1498 *
1499 * @return A stream of resource {@link java.net.URL URL} objects. If no
1500 * resources could be found, the stream will be empty. Resources
1501 * for which a {@code URL} cannot be constructed, are in a package
1502 * that is not opened unconditionally, or access to the resource
1503 * is denied by the security manager, will not be in the stream.
1504 *
1505 * @throws NullPointerException If {@code name} is {@code null}
1506 *
1507 * @since 9
1508 */
1509 public Stream<URL> resources(String name) {
1510 Objects.requireNonNull(name);
1511 int characteristics = Spliterator.NONNULL | Spliterator.IMMUTABLE;
1512 Supplier<Spliterator<URL>> si = () -> {
1513 try {
1514 return Spliterators.spliteratorUnknownSize(
1515 getResources(name).asIterator(), characteristics);
1516 } catch (IOException e) {
1517 throw new UncheckedIOException(e);
1518 }
1519 };
1520 return StreamSupport.stream(si, characteristics, false);
1521 }
1522
1523 /**
1524 * Finds the resource with the given name. Class loader implementations
1525 * should override this method.
1526 *
1527 * <p> For resources in named modules then the method must implement the
1528 * rules for encapsulation specified in the {@code Module} {@link
1529 * Module#getResourceAsStream getResourceAsStream} method. Additionally,
1530 * it must not find non-"{@code .class}" resources in packages of named
1531 * modules unless the package is {@link Module#isOpen(String) opened}
1532 * unconditionally. </p>
1533 *
1534 * @implSpec The default implementation returns {@code null}.
1535 *
1536 * @param name
1537 * The resource name
1538 *
1539 * @return {@code URL} object for reading the resource; {@code null} if
1540 * the resource could not be found, a {@code URL} could not be
1541 * constructed to locate the resource, the resource is in a package
1542 * that is not opened unconditionally, or access to the resource is
1543 * denied by the security manager.
1544 *
1545 * @since 1.2
1546 * @revised 9
1547 * @spec JPMS
1548 */
1549 protected URL findResource(String name) {
1550 return null;
1551 }
1552
1553 /**
1554 * Returns an enumeration of {@link java.net.URL URL} objects
1555 * representing all the resources with the given name. Class loader
1556 * implementations should override this method.
1557 *
1558 * <p> For resources in named modules then the method must implement the
1559 * rules for encapsulation specified in the {@code Module} {@link
1560 * Module#getResourceAsStream getResourceAsStream} method. Additionally,
1561 * it must not find non-"{@code .class}" resources in packages of named
1562 * modules unless the package is {@link Module#isOpen(String) opened}
1563 * unconditionally. </p>
1564 *
1565 * @implSpec The default implementation returns an enumeration that
1566 * contains no elements.
1567 *
1568 * @param name
1569 * The resource name
1570 *
1571 * @return An enumeration of {@link java.net.URL URL} objects for
1572 * the resource. If no resources could be found, the enumeration
1573 * will be empty. Resources for which a {@code URL} cannot be
1574 * constructed, are in a package that is not opened unconditionally,
1575 * or access to the resource is denied by the security manager,
1576 * are not returned in the enumeration.
1577 *
1578 * @throws IOException
1579 * If I/O errors occur
1580 *
1581 * @since 1.2
1582 * @revised 9
1583 * @spec JPMS
1584 */
1585 protected Enumeration<URL> findResources(String name) throws IOException {
1586 return Collections.emptyEnumeration();
1587 }
1588
1589 /**
1590 * Registers the caller as
1591 * {@linkplain #isRegisteredAsParallelCapable() parallel capable}.
1592 * The registration succeeds if and only if all of the following
1593 * conditions are met:
1594 * <ol>
1595 * <li> no instance of the caller has been created</li>
1596 * <li> all of the super classes (except class Object) of the caller are
1597 * registered as parallel capable</li>
1598 * </ol>
1599 * <p>Note that once a class loader is registered as parallel capable, there
1600 * is no way to change it back.</p>
1601 *
1602 * @return {@code true} if the caller is successfully registered as
1603 * parallel capable and {@code false} if otherwise.
1604 *
1605 * @see #isRegisteredAsParallelCapable()
1606 *
1607 * @since 1.7
1608 */
1609 @CallerSensitive
1610 protected static boolean registerAsParallelCapable() {
1611 Class<? extends ClassLoader> callerClass =
1612 Reflection.getCallerClass().asSubclass(ClassLoader.class);
1613 return ParallelLoaders.register(callerClass);
1614 }
1615
1616 /**
1617 * Returns {@code true} if this class loader is registered as
1618 * {@linkplain #registerAsParallelCapable parallel capable}, otherwise
1619 * {@code false}.
1620 *
1621 * @return {@code true} if this class loader is parallel capable,
1622 * otherwise {@code false}.
1623 *
1624 * @see #registerAsParallelCapable()
1625 *
1626 * @since 9
1627 */
1628 public final boolean isRegisteredAsParallelCapable() {
1629 return ParallelLoaders.isRegistered(this.getClass());
1630 }
1631
1632 /**
1633 * Find a resource of the specified name from the search path used to load
1634 * classes. This method locates the resource through the system class
1635 * loader (see {@link #getSystemClassLoader()}).
1636 *
1637 * <p> Resources in named modules are subject to the encapsulation rules
1638 * specified by {@link Module#getResourceAsStream Module.getResourceAsStream}.
1639 * Additionally, and except for the special case where the resource has a
1640 * name ending with "{@code .class}", this method will only find resources in
1641 * packages of named modules when the package is {@link Module#isOpen(String)
1642 * opened} unconditionally. </p>
1643 *
1644 * @param name
1645 * The resource name
1646 *
1647 * @return A {@link java.net.URL URL} to the resource; {@code
1648 * null} if the resource could not be found, a URL could not be
1649 * constructed to locate the resource, the resource is in a package
1650 * that is not opened unconditionally or access to the resource is
1651 * denied by the security manager.
1652 *
1653 * @since 1.1
1654 * @revised 9
1655 * @spec JPMS
1656 */
1657 public static URL getSystemResource(String name) {
1658 return getSystemClassLoader().getResource(name);
1659 }
1660
1661 /**
1662 * Finds all resources of the specified name from the search path used to
1663 * load classes. The resources thus found are returned as an
1664 * {@link java.util.Enumeration Enumeration} of {@link
1665 * java.net.URL URL} objects.
1666 *
1667 * <p> The search order is described in the documentation for {@link
1668 * #getSystemResource(String)}. </p>
1669 *
1670 * <p> Resources in named modules are subject to the encapsulation rules
1671 * specified by {@link Module#getResourceAsStream Module.getResourceAsStream}.
1672 * Additionally, and except for the special case where the resource has a
1673 * name ending with "{@code .class}", this method will only find resources in
1674 * packages of named modules when the package is {@link Module#isOpen(String)
1675 * opened} unconditionally. </p>
1676 *
1677 * @param name
1678 * The resource name
1679 *
1680 * @return An enumeration of {@link java.net.URL URL} objects for
1681 * the resource. If no resources could be found, the enumeration
1682 * will be empty. Resources for which a {@code URL} cannot be
1683 * constructed, are in a package that is not opened unconditionally,
1684 * or access to the resource is denied by the security manager,
1685 * are not returned in the enumeration.
1686 *
1687 * @throws IOException
1688 * If I/O errors occur
1689 *
1690 * @since 1.2
1691 * @revised 9
1692 * @spec JPMS
1693 */
1694 public static Enumeration<URL> getSystemResources(String name)
1695 throws IOException
1696 {
1697 return getSystemClassLoader().getResources(name);
1698 }
1699
1700 /**
1701 * Returns an input stream for reading the specified resource.
1702 *
1703 * <p> The search order is described in the documentation for {@link
1704 * #getResource(String)}. </p>
1705 *
1706 * <p> Resources in named modules are subject to the encapsulation rules
1707 * specified by {@link Module#getResourceAsStream Module.getResourceAsStream}.
1708 * Additionally, and except for the special case where the resource has a
1709 * name ending with "{@code .class}", this method will only find resources in
1710 * packages of named modules when the package is {@link Module#isOpen(String)
1711 * opened} unconditionally. </p>
1712 *
1713 * @param name
1714 * The resource name
1715 *
1716 * @return An input stream for reading the resource; {@code null} if the
1717 * resource could not be found, the resource is in a package that
1718 * is not opened unconditionally, or access to the resource is
1719 * denied by the security manager.
1720 *
1721 * @throws NullPointerException If {@code name} is {@code null}
1722 *
1723 * @since 1.1
1724 * @revised 9
1725 * @spec JPMS
1726 */
1727 public InputStream getResourceAsStream(String name) {
1728 Objects.requireNonNull(name);
1729 URL url = getResource(name);
1730 try {
1731 return url != null ? url.openStream() : null;
1732 } catch (IOException e) {
1733 return null;
1734 }
1735 }
1736
1737 /**
1738 * Open for reading, a resource of the specified name from the search path
1739 * used to load classes. This method locates the resource through the
1740 * system class loader (see {@link #getSystemClassLoader()}).
1741 *
1742 * <p> Resources in named modules are subject to the encapsulation rules
1743 * specified by {@link Module#getResourceAsStream Module.getResourceAsStream}.
1744 * Additionally, and except for the special case where the resource has a
1745 * name ending with "{@code .class}", this method will only find resources in
1746 * packages of named modules when the package is {@link Module#isOpen(String)
1747 * opened} unconditionally. </p>
1748 *
1749 * @param name
1750 * The resource name
1751 *
1752 * @return An input stream for reading the resource; {@code null} if the
1753 * resource could not be found, the resource is in a package that
1754 * is not opened unconditionally, or access to the resource is
1755 * denied by the security manager.
1756 *
1757 * @since 1.1
1758 * @revised 9
1759 * @spec JPMS
1760 */
1761 public static InputStream getSystemResourceAsStream(String name) {
1762 URL url = getSystemResource(name);
1763 try {
1764 return url != null ? url.openStream() : null;
1765 } catch (IOException e) {
1766 return null;
1767 }
1768 }
1769
1770
1771 // -- Hierarchy --
1772
1773 /**
1774 * Returns the parent class loader for delegation. Some implementations may
1775 * use {@code null} to represent the bootstrap class loader. This method
1776 * will return {@code null} in such implementations if this class loader's
1777 * parent is the bootstrap class loader.
1778 *
1779 * @return The parent {@code ClassLoader}
1780 *
1781 * @throws SecurityException
1782 * If a security manager is present, and the caller's class loader
1783 * is not {@code null} and is not an ancestor of this class loader,
1784 * and the caller does not have the
1785 * {@link RuntimePermission}{@code ("getClassLoader")}
1786 *
1787 * @since 1.2
1788 */
1789 @CallerSensitive
1790 public final ClassLoader getParent() {
1791 if (parent == null)
1792 return null;
1793 SecurityManager sm = System.getSecurityManager();
1794 if (sm != null) {
1795 // Check access to the parent class loader
1796 // If the caller's class loader is same as this class loader,
1797 // permission check is performed.
1798 checkClassLoaderPermission(parent, Reflection.getCallerClass());
1799 }
1800 return parent;
1801 }
1802
1803 /**
1804 * Returns the unnamed {@code Module} for this class loader.
1805 *
1806 * @return The unnamed Module for this class loader
1807 *
1808 * @see Module#isNamed()
1809 * @since 9
1810 * @spec JPMS
1811 */
1812 public final Module getUnnamedModule() {
1813 return unnamedModule;
1814 }
1815
1816 /**
1817 * Returns the platform class loader for delegation. All
1818 * <a href="#builtinLoaders">platform classes</a> are visible to
1819 * the platform class loader.
1820 *
1821 * @implNote The name of the builtin platform class loader is
1822 * {@code "platform"}.
1823 *
1824 * @return The platform {@code ClassLoader}.
1825 *
1826 * @throws SecurityException
1827 * If a security manager is present, and the caller's class loader is
1828 * not {@code null}, and the caller's class loader is not the same
1829 * as or an ancestor of the platform class loader,
1830 * and the caller does not have the
1831 * {@link RuntimePermission}{@code ("getClassLoader")}
1832 *
1833 * @since 9
1834 * @spec JPMS
1835 */
1836 @CallerSensitive
1837 public static ClassLoader getPlatformClassLoader() {
1838 SecurityManager sm = System.getSecurityManager();
1839 ClassLoader loader = getBuiltinPlatformClassLoader();
1840 if (sm != null) {
1841 checkClassLoaderPermission(loader, Reflection.getCallerClass());
1842 }
1843 return loader;
1844 }
1845
1846 /**
1847 * Returns the system class loader for delegation. This is the default
1848 * delegation parent for new {@code ClassLoader} instances, and is
1849 * typically the class loader used to start the application.
1850 *
1851 * <p> This method is first invoked early in the runtime's startup
1852 * sequence, at which point it creates the system class loader. This
1853 * class loader will be the context class loader for the main application
1854 * thread (for example, the thread that invokes the {@code main} method of
1855 * the main class).
1856 *
1857 * <p> The default system class loader is an implementation-dependent
1858 * instance of this class.
1859 *
1860 * <p> If the system property "{@code java.system.class.loader}" is defined
1861 * when this method is first invoked then the value of that property is
1862 * taken to be the name of a class that will be returned as the system
1863 * class loader. The class is loaded using the default system class loader
1864 * and must define a public constructor that takes a single parameter of
1865 * type {@code ClassLoader} which is used as the delegation parent. An
1866 * instance is then created using this constructor with the default system
1867 * class loader as the parameter. The resulting class loader is defined
1868 * to be the system class loader. During construction, the class loader
1869 * should take great care to avoid calling {@code getSystemClassLoader()}.
1870 * If circular initialization of the system class loader is detected then
1871 * an unspecified error or exception is thrown.
1872 *
1873 * @implNote The system property to override the system class loader is not
1874 * examined until the VM is almost fully initialized. Code that executes
1875 * this method during startup should take care not to cache the return
1876 * value until the system is fully initialized.
1877 *
1878 * <p> The name of the built-in system class loader is {@code "app"}.
1879 * The class path used by the built-in system class loader is determined
1880 * by the system property "{@code java.class.path}" during early
1881 * initialization of the VM. If the system property is not defined,
1882 * or its value is an empty string, then there is no class path
1883 * when the initial module is a module on the application module path,
1884 * i.e. <em>a named module</em>. If the initial module is not on
1885 * the application module path then the class path defaults to
1886 * the current working directory.
1887 *
1888 * @return The system {@code ClassLoader} for delegation
1889 *
1890 * @throws SecurityException
1891 * If a security manager is present, and the caller's class loader
1892 * is not {@code null} and is not the same as or an ancestor of the
1893 * system class loader, and the caller does not have the
1894 * {@link RuntimePermission}{@code ("getClassLoader")}
1895 *
1896 * @throws IllegalStateException
1897 * If invoked recursively during the construction of the class
1898 * loader specified by the "{@code java.system.class.loader}"
1899 * property.
1900 *
1901 * @throws Error
1902 * If the system property "{@code java.system.class.loader}"
1903 * is defined but the named class could not be loaded, the
1904 * provider class does not define the required constructor, or an
1905 * exception is thrown by that constructor when it is invoked. The
1906 * underlying cause of the error can be retrieved via the
1907 * {@link Throwable#getCause()} method.
1908 *
1909 * @revised 1.4
1910 * @revised 9
1911 * @spec JPMS
1912 */
1913 @CallerSensitive
1914 public static ClassLoader getSystemClassLoader() {
1915 switch (VM.initLevel()) {
1916 case 0:
1917 case 1:
1918 case 2:
1919 // the system class loader is the built-in app class loader during startup
1920 return getBuiltinAppClassLoader();
1921 case 3:
1922 String msg = "getSystemClassLoader should only be called after VM booted";
1923 throw new InternalError(msg);
1924 case 4:
1925 // system fully initialized
1926 assert VM.isBooted() && scl != null;
1927 SecurityManager sm = System.getSecurityManager();
1928 if (sm != null) {
1929 checkClassLoaderPermission(scl, Reflection.getCallerClass());
1930 }
1931 return scl;
1932 default:
1933 throw new InternalError("should not reach here");
1934 }
1935 }
1936
1937 static ClassLoader getBuiltinPlatformClassLoader() {
1938 return ClassLoaders.platformClassLoader();
1939 }
1940
1941 static ClassLoader getBuiltinAppClassLoader() {
1942 return ClassLoaders.appClassLoader();
1943 }
1944
1945 /*
1946 * Initialize the system class loader that may be a custom class on the
1947 * application class path or application module path.
1948 *
1949 * @see java.lang.System#initPhase3
1950 */
1951 static synchronized ClassLoader initSystemClassLoader() {
1952 if (VM.initLevel() != 3) {
1953 throw new InternalError("system class loader cannot be set at initLevel " +
1954 VM.initLevel());
1955 }
1956
1957 // detect recursive initialization
1958 if (scl != null) {
1959 throw new IllegalStateException("recursive invocation");
1960 }
1961
1962 ClassLoader builtinLoader = getBuiltinAppClassLoader();
1963
1964 // All are privileged frames. No need to call doPrivileged.
1965 String cn = System.getProperty("java.system.class.loader");
1966 if (cn != null) {
1967 try {
1968 // custom class loader is only supported to be loaded from unnamed module
1969 Constructor<?> ctor = Class.forName(cn, false, builtinLoader)
1970 .getDeclaredConstructor(ClassLoader.class);
1971 scl = (ClassLoader) ctor.newInstance(builtinLoader);
1972 } catch (Exception e) {
1973 throw new Error(e);
1974 }
1975 } else {
1976 scl = builtinLoader;
1977 }
1978 return scl;
1979 }
1980
1981 // Returns true if the specified class loader can be found in this class
1982 // loader's delegation chain.
1983 boolean isAncestor(ClassLoader cl) {
1984 ClassLoader acl = this;
1985 do {
1986 acl = acl.parent;
1987 if (cl == acl) {
1988 return true;
1989 }
1990 } while (acl != null);
1991 return false;
1992 }
1993
1994 // Tests if class loader access requires "getClassLoader" permission
1995 // check. A class loader 'from' can access class loader 'to' if
1996 // class loader 'from' is same as class loader 'to' or an ancestor
1997 // of 'to'. The class loader in a system domain can access
1998 // any class loader.
1999 private static boolean needsClassLoaderPermissionCheck(ClassLoader from,
2000 ClassLoader to)
2001 {
2002 if (from == to)
2003 return false;
2004
2005 if (from == null)
2006 return false;
2007
2008 return !to.isAncestor(from);
2009 }
2010
2011 // Returns the class's class loader, or null if none.
2012 static ClassLoader getClassLoader(Class<?> caller) {
2013 // This can be null if the VM is requesting it
2014 if (caller == null) {
2015 return null;
2016 }
2017 // Circumvent security check since this is package-private
2018 return caller.getClassLoader0();
2019 }
2020
2021 /*
2022 * Checks RuntimePermission("getClassLoader") permission
2023 * if caller's class loader is not null and caller's class loader
2024 * is not the same as or an ancestor of the given cl argument.
2025 */
2026 static void checkClassLoaderPermission(ClassLoader cl, Class<?> caller) {
2027 SecurityManager sm = System.getSecurityManager();
2028 if (sm != null) {
2029 // caller can be null if the VM is requesting it
2030 ClassLoader ccl = getClassLoader(caller);
2031 if (needsClassLoaderPermissionCheck(ccl, cl)) {
2032 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
2033 }
2034 }
2035 }
2036
2037 // The system class loader
2038 // @GuardedBy("ClassLoader.class")
2039 private static volatile ClassLoader scl;
2040
2041 // -- Package --
2042
2043 /**
2044 * Define a Package of the given Class object.
2045 *
2046 * If the given class represents an array type, a primitive type or void,
2047 * this method returns {@code null}.
2048 *
2049 * This method does not throw IllegalArgumentException.
2050 */
2051 Package definePackage(Class<?> c) {
2052 if (c.isPrimitive() || c.isArray()) {
2053 return null;
2054 }
2055
2056 return definePackage(c.getPackageName(), c.getModule());
2057 }
2058
2059 /**
2060 * Defines a Package of the given name and module
2061 *
2062 * This method does not throw IllegalArgumentException.
2063 *
2064 * @param name package name
2065 * @param m module
2066 */
2067 Package definePackage(String name, Module m) {
2068 if (name.isEmpty() && m.isNamed()) {
2069 throw new InternalError("unnamed package in " + m);
2070 }
2071
2072 // check if Package object is already defined
2073 NamedPackage pkg = packages.get(name);
2074 if (pkg instanceof Package)
2075 return (Package)pkg;
2076
2077 return (Package)packages.compute(name, (n, p) -> toPackage(n, p, m));
2078 }
2079
2080 /*
2081 * Returns a Package object for the named package
2082 */
2083 private Package toPackage(String name, NamedPackage p, Module m) {
2084 // define Package object if the named package is not yet defined
2085 if (p == null)
2086 return NamedPackage.toPackage(name, m);
2087
2088 // otherwise, replace the NamedPackage object with Package object
2089 if (p instanceof Package)
2090 return (Package)p;
2091
2092 return NamedPackage.toPackage(p.packageName(), p.module());
2093 }
2094
2095 /**
2096 * Defines a package by <a href="#name">name</a> in this {@code ClassLoader}.
2097 * <p>
2098 * <a href="#name">Package names</a> must be unique within a class loader and
2099 * cannot be redefined or changed once created.
2100 * <p>
2101 * If a class loader wishes to define a package with specific properties,
2102 * such as version information, then the class loader should call this
2103 * {@code definePackage} method before calling {@code defineClass}.
2104 * Otherwise, the
2105 * {@link #defineClass(String, byte[], int, int, ProtectionDomain) defineClass}
2106 * method will define a package in this class loader corresponding to the package
2107 * of the newly defined class; the properties of this defined package are
2108 * specified by {@link Package}.
2109 *
2110 * @apiNote
2111 * A class loader that wishes to define a package for classes in a JAR
2112 * typically uses the specification and implementation titles, versions, and
2113 * vendors from the JAR's manifest. If the package is specified as
2114 * {@linkplain java.util.jar.Attributes.Name#SEALED sealed} in the JAR's manifest,
2115 * the {@code URL} of the JAR file is typically used as the {@code sealBase}.
2116 * If classes of package {@code 'p'} defined by this class loader
2117 * are loaded from multiple JARs, the {@code Package} object may contain
2118 * different information depending on the first class of package {@code 'p'}
2119 * defined and which JAR's manifest is read first to explicitly define
2120 * package {@code 'p'}.
2121 *
2122 * <p> It is strongly recommended that a class loader does not call this
2123 * method to explicitly define packages in <em>named modules</em>; instead,
2124 * the package will be automatically defined when a class is {@linkplain
2125 * #defineClass(String, byte[], int, int, ProtectionDomain) being defined}.
2126 * If it is desirable to define {@code Package} explicitly, it should ensure
2127 * that all packages in a named module are defined with the properties
2128 * specified by {@link Package}. Otherwise, some {@code Package} objects
2129 * in a named module may be for example sealed with different seal base.
2130 *
2131 * @param name
2132 * The <a href="#name">package name</a>
2133 *
2134 * @param specTitle
2135 * The specification title
2136 *
2137 * @param specVersion
2138 * The specification version
2139 *
2140 * @param specVendor
2141 * The specification vendor
2142 *
2143 * @param implTitle
2144 * The implementation title
2145 *
2146 * @param implVersion
2147 * The implementation version
2148 *
2149 * @param implVendor
2150 * The implementation vendor
2151 *
2152 * @param sealBase
2153 * If not {@code null}, then this package is sealed with
2154 * respect to the given code source {@link java.net.URL URL}
2155 * object. Otherwise, the package is not sealed.
2156 *
2157 * @return The newly defined {@code Package} object
2158 *
2159 * @throws NullPointerException
2160 * if {@code name} is {@code null}.
2161 *
2162 * @throws IllegalArgumentException
2163 * if a package of the given {@code name} is already
2164 * defined by this class loader
2165 *
2166 *
2167 * @since 1.2
2168 * @revised 9
2169 * @spec JPMS
2170 *
2171 * @jvms 5.3 Run-time package
2172 * @see <a href="{@docRoot}/../specs/jar/jar.html#sealing">
2173 * The JAR File Specification: Package Sealing</a>
2174 */
2175 protected Package definePackage(String name, String specTitle,
2176 String specVersion, String specVendor,
2177 String implTitle, String implVersion,
2178 String implVendor, URL sealBase)
2179 {
2180 Objects.requireNonNull(name);
2181
2182 // definePackage is not final and may be overridden by custom class loader
2183 Package p = new Package(name, specTitle, specVersion, specVendor,
2184 implTitle, implVersion, implVendor,
2185 sealBase, this);
2186
2187 if (packages.putIfAbsent(name, p) != null)
2188 throw new IllegalArgumentException(name);
2189
2190 return p;
2191 }
2192
2193 /**
2194 * Returns a {@code Package} of the given <a href="#name">name</a> that
2195 * has been defined by this class loader.
2196 *
2197 * @param name The <a href="#name">package name</a>
2198 *
2199 * @return The {@code Package} of the given name that has been defined
2200 * by this class loader, or {@code null} if not found
2201 *
2202 * @throws NullPointerException
2203 * if {@code name} is {@code null}.
2204 *
2205 * @jvms 5.3 Run-time package
2206 *
2207 * @since 9
2208 * @spec JPMS
2209 */
2210 public final Package getDefinedPackage(String name) {
2211 Objects.requireNonNull(name, "name cannot be null");
2212
2213 NamedPackage p = packages.get(name);
2214 if (p == null)
2215 return null;
2216
2217 return definePackage(name, p.module());
2218 }
2219
2220 /**
2221 * Returns all of the {@code Package}s that have been defined by
2222 * this class loader. The returned array has no duplicated {@code Package}s
2223 * of the same name.
2224 *
2225 * @apiNote This method returns an array rather than a {@code Set} or {@code Stream}
2226 * for consistency with the existing {@link #getPackages} method.
2227 *
2228 * @return The array of {@code Package} objects that have been defined by
2229 * this class loader; or an zero length array if no package has been
2230 * defined by this class loader.
2231 *
2232 * @jvms 5.3 Run-time package
2233 *
2234 * @since 9
2235 * @spec JPMS
2236 */
2237 public final Package[] getDefinedPackages() {
2238 return packages().toArray(Package[]::new);
2239 }
2240
2241 /**
2242 * Finds a package by <a href="#name">name</a> in this class loader and its ancestors.
2243 * <p>
2244 * If this class loader defines a {@code Package} of the given name,
2245 * the {@code Package} is returned. Otherwise, the ancestors of
2246 * this class loader are searched recursively (parent by parent)
2247 * for a {@code Package} of the given name.
2248 *
2249 * @apiNote The {@link #getPlatformClassLoader() platform class loader}
2250 * may delegate to the application class loader but the application class
2251 * loader is not its ancestor. When invoked on the platform class loader,
2252 * this method will not find packages defined to the application
2253 * class loader.
2254 *
2255 * @param name
2256 * The <a href="#name">package name</a>
2257 *
2258 * @return The {@code Package} of the given name that has been defined by
2259 * this class loader or its ancestors, or {@code null} if not found.
2260 *
2261 * @throws NullPointerException
2262 * if {@code name} is {@code null}.
2263 *
2264 * @deprecated
2265 * If multiple class loaders delegate to each other and define classes
2266 * with the same package name, and one such loader relies on the lookup
2267 * behavior of {@code getPackage} to return a {@code Package} from
2268 * a parent loader, then the properties exposed by the {@code Package}
2269 * may not be as expected in the rest of the program.
2270 * For example, the {@code Package} will only expose annotations from the
2271 * {@code package-info.class} file defined by the parent loader, even if
2272 * annotations exist in a {@code package-info.class} file defined by
2273 * a child loader. A more robust approach is to use the
2274 * {@link ClassLoader#getDefinedPackage} method which returns
2275 * a {@code Package} for the specified class loader.
2276 *
2277 * @see ClassLoader#getDefinedPackage(String)
2278 *
2279 * @since 1.2
2280 * @revised 9
2281 * @spec JPMS
2282 */
2283 @Deprecated(since="9")
2284 protected Package getPackage(String name) {
2285 Package pkg = getDefinedPackage(name);
2286 if (pkg == null) {
2287 if (parent != null) {
2288 pkg = parent.getPackage(name);
2289 } else {
2290 pkg = BootLoader.getDefinedPackage(name);
2291 }
2292 }
2293 return pkg;
2294 }
2295
2296 /**
2297 * Returns all of the {@code Package}s that have been defined by
2298 * this class loader and its ancestors. The returned array may contain
2299 * more than one {@code Package} object of the same package name, each
2300 * defined by a different class loader in the class loader hierarchy.
2301 *
2302 * @apiNote The {@link #getPlatformClassLoader() platform class loader}
2303 * may delegate to the application class loader. In other words,
2304 * packages in modules defined to the application class loader may be
2305 * visible to the platform class loader. On the other hand,
2306 * the application class loader is not its ancestor and hence
2307 * when invoked on the platform class loader, this method will not
2308 * return any packages defined to the application class loader.
2309 *
2310 * @return The array of {@code Package} objects that have been defined by
2311 * this class loader and its ancestors
2312 *
2313 * @see ClassLoader#getDefinedPackages()
2314 *
2315 * @since 1.2
2316 * @revised 9
2317 * @spec JPMS
2318 */
2319 protected Package[] getPackages() {
2320 Stream<Package> pkgs = packages();
2321 ClassLoader ld = parent;
2322 while (ld != null) {
2323 pkgs = Stream.concat(ld.packages(), pkgs);
2324 ld = ld.parent;
2325 }
2326 return Stream.concat(BootLoader.packages(), pkgs)
2327 .toArray(Package[]::new);
2328 }
2329
2330
2331
2332 // package-private
2333
2334 /**
2335 * Returns a stream of Packages defined in this class loader
2336 */
2337 Stream<Package> packages() {
2338 return packages.values().stream()
2339 .map(p -> definePackage(p.packageName(), p.module()));
2340 }
2341
2342 // -- Native library access --
2343
2344 /**
2345 * Returns the absolute path name of a native library. The VM invokes this
2346 * method to locate the native libraries that belong to classes loaded with
2347 * this class loader. If this method returns {@code null}, the VM
2348 * searches the library along the path specified as the
2349 * "{@code java.library.path}" property.
2350 *
2351 * @param libname
2352 * The library name
2353 *
2354 * @return The absolute path of the native library
2355 *
2356 * @see System#loadLibrary(String)
2357 * @see System#mapLibraryName(String)
2358 *
2359 * @since 1.2
2360 */
2361 protected String findLibrary(String libname) {
2362 return null;
2363 }
2364
2365 /**
2366 * The inner class NativeLibrary denotes a loaded native library instance.
2367 * Every classloader contains a vector of loaded native libraries in the
2368 * private field {@code nativeLibraries}. The native libraries loaded
2369 * into the system are entered into the {@code systemNativeLibraries}
2370 * vector.
2371 *
2372 * <p> Every native library requires a particular version of JNI. This is
2373 * denoted by the private {@code jniVersion} field. This field is set by
2374 * the VM when it loads the library, and used by the VM to pass the correct
2375 * version of JNI to the native methods. </p>
2376 *
2377 * @see ClassLoader
2378 * @since 1.2
2379 */
2380 static class NativeLibrary {
2381 // the class from which the library is loaded, also indicates
2382 // the loader this native library belongs.
2383 final Class<?> fromClass;
2384 // the canonicalized name of the native library.
2385 // or static library name
2386 final String name;
2387 // Indicates if the native library is linked into the VM
2388 final boolean isBuiltin;
2389
2390 // opaque handle to native library, used in native code.
2391 long handle;
2392 // the version of JNI environment the native library requires.
2393 int jniVersion;
2394
2395 native boolean load0(String name, boolean isBuiltin);
2396
2397 native long findEntry(String name);
2398
2399 NativeLibrary(Class<?> fromClass, String name, boolean isBuiltin) {
2400 this.name = name;
2401 this.fromClass = fromClass;
2402 this.isBuiltin = isBuiltin;
2403 }
2404
2405 /*
2406 * Loads the native library and registers for cleanup when its
2407 * associated class loader is unloaded
2408 */
2409 boolean load() {
2410 if (handle != 0) {
2411 throw new InternalError("Native library " + name + " has been loaded");
2412 }
2413
2414 if (!load0(name, isBuiltin)) return false;
2415
2416 // register the class loader for cleanup when unloaded
2417 // built class loaders are never unloaded
2418 ClassLoader loader = fromClass.getClassLoader();
2419 if (loader != null &&
2420 loader != getBuiltinPlatformClassLoader() &&
2421 loader != getBuiltinAppClassLoader()) {
2422 CleanerFactory.cleaner().register(loader,
2423 new Unloader(name, handle, isBuiltin));
2424 }
2425 return true;
2426 }
2427
2428 static boolean loadLibrary(Class<?> fromClass, String name, boolean isBuiltin) {
2429 ClassLoader loader =
2430 fromClass == null ? null : fromClass.getClassLoader();
2431
2432 synchronized (loadedLibraryNames) {
2433 Map<String, NativeLibrary> libs =
2434 loader != null ? loader.nativeLibraries() : systemNativeLibraries();
2435 if (libs.containsKey(name)) {
2436 return true;
2437 }
2438
2439 if (loadedLibraryNames.contains(name)) {
2440 throw new UnsatisfiedLinkError("Native Library " + name +
2441 " already loaded in another classloader");
2442 }
2443
2444 /*
2445 * When a library is being loaded, JNI_OnLoad function can cause
2446 * another loadLibrary invocation that should succeed.
2447 *
2448 * We use a static stack to hold the list of libraries we are
2449 * loading because this can happen only when called by the
2450 * same thread because Runtime.load and Runtime.loadLibrary
2451 * are synchronous.
2452 *
2453 * If there is a pending load operation for the library, we
2454 * immediately return success; otherwise, we raise
2455 * UnsatisfiedLinkError.
2456 */
2457 for (NativeLibrary lib : nativeLibraryContext) {
2458 if (name.equals(lib.name)) {
2459 if (loader == lib.fromClass.getClassLoader()) {
2460 return true;
2461 } else {
2462 throw new UnsatisfiedLinkError("Native Library " +
2463 name + " is being loaded in another classloader");
2464 }
2465 }
2466 }
2467 NativeLibrary lib = new NativeLibrary(fromClass, name, isBuiltin);
2468 // load the native library
2469 nativeLibraryContext.push(lib);
2470 try {
2471 if (!lib.load()) return false;
2472 } finally {
2473 nativeLibraryContext.pop();
2474 }
2475 // register the loaded native library
2476 loadedLibraryNames.add(name);
2477 libs.put(name, lib);
2478 }
2479 return true;
2480 }
2481
2482 // Invoked in the VM to determine the context class in JNI_OnLoad
2483 // and JNI_OnUnload
2484 static Class<?> getFromClass() {
2485 return nativeLibraryContext.peek().fromClass;
2486 }
2487
2488 // native libraries being loaded
2489 static Deque<NativeLibrary> nativeLibraryContext = new LinkedList<>();
2490
2491 /*
2492 * The run() method will be invoked when this class loader becomes
2493 * phantom reachable to unload the native library.
2494 */
2495 static class Unloader implements Runnable {
2496 // This represents the context when a native library is unloaded
2497 // and getFromClass() will return null,
2498 static final NativeLibrary UNLOADER =
2499 new NativeLibrary(null, "dummy", false);
2500 final String name;
2501 final long handle;
2502 final boolean isBuiltin;
2503
2504 Unloader(String name, long handle, boolean isBuiltin) {
2505 if (handle == 0) {
2506 throw new IllegalArgumentException(
2507 "Invalid handle for native library " + name);
2508 }
2509
2510 this.name = name;
2511 this.handle = handle;
2512 this.isBuiltin = isBuiltin;
2513 }
2514
2515 @Override
2516 public void run() {
2517 synchronized (loadedLibraryNames) {
2518 /* remove the native library name */
2519 loadedLibraryNames.remove(name);
2520 nativeLibraryContext.push(UNLOADER);
2521 try {
2522 unload(name, isBuiltin, handle);
2523 } finally {
2524 nativeLibraryContext.pop();
2525 }
2526
2527 }
2528 }
2529 }
2530
2531 // JNI FindClass expects the caller class if invoked from JNI_OnLoad
2532 // and JNI_OnUnload is NativeLibrary class
2533 static native void unload(String name, boolean isBuiltin, long handle);
2534 }
2535
2536 // The paths searched for libraries
2537 private static String usr_paths[];
2538 private static String sys_paths[];
2539
2540 private static String[] initializePath(String propName) {
2541 String ldPath = System.getProperty(propName, "");
2542 int ldLen = ldPath.length();
2543 char ps = File.pathSeparatorChar;
2544 int psCount = 0;
2545
2546 if (ClassLoaderHelper.allowsQuotedPathElements &&
2547 ldPath.indexOf('\"') >= 0) {
2548 // First, remove quotes put around quoted parts of paths.
2549 // Second, use a quotation mark as a new path separator.
2550 // This will preserve any quoted old path separators.
2551 char[] buf = new char[ldLen];
2552 int bufLen = 0;
2553 for (int i = 0; i < ldLen; ++i) {
2554 char ch = ldPath.charAt(i);
2555 if (ch == '\"') {
2556 while (++i < ldLen &&
2557 (ch = ldPath.charAt(i)) != '\"') {
2558 buf[bufLen++] = ch;
2559 }
2560 } else {
2561 if (ch == ps) {
2562 psCount++;
2563 ch = '\"';
2564 }
2565 buf[bufLen++] = ch;
2566 }
2567 }
2568 ldPath = new String(buf, 0, bufLen);
2569 ldLen = bufLen;
2570 ps = '\"';
2571 } else {
2572 for (int i = ldPath.indexOf(ps); i >= 0;
2573 i = ldPath.indexOf(ps, i + 1)) {
2574 psCount++;
2575 }
2576 }
2577
2578 String[] paths = new String[psCount + 1];
2579 int pathStart = 0;
2580 for (int j = 0; j < psCount; ++j) {
2581 int pathEnd = ldPath.indexOf(ps, pathStart);
2582 paths[j] = (pathStart < pathEnd) ?
2583 ldPath.substring(pathStart, pathEnd) : ".";
2584 pathStart = pathEnd + 1;
2585 }
2586 paths[psCount] = (pathStart < ldLen) ?
2587 ldPath.substring(pathStart, ldLen) : ".";
2588 return paths;
2589 }
2590
2591 // Invoked in the java.lang.Runtime class to implement load and loadLibrary.
2592 static void loadLibrary(Class<?> fromClass, String name,
2593 boolean isAbsolute) {
2594 ClassLoader loader =
2595 (fromClass == null) ? null : fromClass.getClassLoader();
2596 if (sys_paths == null) {
2597 usr_paths = initializePath("java.library.path");
2598 sys_paths = initializePath("sun.boot.library.path");
2599 }
2600 if (isAbsolute) {
2601 if (loadLibrary0(fromClass, new File(name))) {
2602 return;
2603 }
2604 throw new UnsatisfiedLinkError("Can't load library: " + name);
2605 }
2606 if (loader != null) {
2607 String libfilename = loader.findLibrary(name);
2608 if (libfilename != null) {
2609 File libfile = new File(libfilename);
2610 if (!libfile.isAbsolute()) {
2611 throw new UnsatisfiedLinkError(
2612 "ClassLoader.findLibrary failed to return an absolute path: " + libfilename);
2613 }
2614 if (loadLibrary0(fromClass, libfile)) {
2615 return;
2616 }
2617 throw new UnsatisfiedLinkError("Can't load " + libfilename);
2618 }
2619 }
2620 for (String sys_path : sys_paths) {
2621 File libfile = new File(sys_path, System.mapLibraryName(name));
2622 if (loadLibrary0(fromClass, libfile)) {
2623 return;
2624 }
2625 libfile = ClassLoaderHelper.mapAlternativeName(libfile);
2626 if (libfile != null && loadLibrary0(fromClass, libfile)) {
2627 return;
2628 }
2629 }
2630 if (loader != null) {
2631 for (String usr_path : usr_paths) {
2632 File libfile = new File(usr_path, System.mapLibraryName(name));
2633 if (loadLibrary0(fromClass, libfile)) {
2634 return;
2635 }
2636 libfile = ClassLoaderHelper.mapAlternativeName(libfile);
2637 if (libfile != null && loadLibrary0(fromClass, libfile)) {
2638 return;
2639 }
2640 }
2641 }
2642 // Oops, it failed
2643 throw new UnsatisfiedLinkError("no " + name +
2644 " in java.library.path: " + Arrays.toString(usr_paths));
2645 }
2646
2647 private static native String findBuiltinLib(String name);
2648
2649 private static boolean loadLibrary0(Class<?> fromClass, final File file) {
2650 // Check to see if we're attempting to access a static library
2651 String name = findBuiltinLib(file.getName());
2652 boolean isBuiltin = (name != null);
2653 if (!isBuiltin) {
2654 name = AccessController.doPrivileged(
2655 new PrivilegedAction<>() {
2656 public String run() {
2657 try {
2658 return file.exists() ? file.getCanonicalPath() : null;
2659 } catch (IOException e) {
2660 return null;
2661 }
2662 }
2663 });
2664 if (name == null) {
2665 return false;
2666 }
2667 }
2668 return NativeLibrary.loadLibrary(fromClass, name, isBuiltin);
2669 }
2670
2671 /*
2672 * Invoked in the VM class linking code.
2673 */
2674 private static long findNative(ClassLoader loader, String name) {
2675 Map<String, NativeLibrary> libs =
2676 loader != null ? loader.nativeLibraries() : systemNativeLibraries();
2677 if (libs.isEmpty())
2678 return 0;
2679
2680 // the native libraries map may be updated in another thread
2681 // when a native library is being loaded. No symbol will be
2682 // searched from it yet.
2683 for (NativeLibrary lib : libs.values()) {
2684 long entry = lib.findEntry(name);
2685 if (entry != 0) return entry;
2686 }
2687 return 0;
2688 }
2689
2690 // All native library names we've loaded.
2691 // This also serves as the lock to obtain nativeLibraries
2692 // and write to nativeLibraryContext.
2693 private static final Set<String> loadedLibraryNames = new HashSet<>();
2694
2695 // Native libraries belonging to system classes.
2696 private static volatile Map<String, NativeLibrary> systemNativeLibraries;
2697
2698 // Native libraries associated with the class loader.
2699 private volatile Map<String, NativeLibrary> nativeLibraries;
2700
2701 /*
2702 * Returns the native libraries map associated with bootstrap class loader
2703 * This method will create the map at the first time when called.
2704 */
2705 private static Map<String, NativeLibrary> systemNativeLibraries() {
2706 Map<String, NativeLibrary> libs = systemNativeLibraries;
2707 if (libs == null) {
2708 synchronized (loadedLibraryNames) {
2709 libs = systemNativeLibraries;
2710 if (libs == null) {
2711 libs = systemNativeLibraries = new ConcurrentHashMap<>();
2712 }
2713 }
2714 }
2715 return libs;
2716 }
2717
2718 /*
2719 * Returns the native libraries map associated with this class loader
2720 * This method will create the map at the first time when called.
2721 */
2722 private Map<String, NativeLibrary> nativeLibraries() {
2723 Map<String, NativeLibrary> libs = nativeLibraries;
2724 if (libs == null) {
2725 synchronized (loadedLibraryNames) {
2726 libs = nativeLibraries;
2727 if (libs == null) {
2728 libs = nativeLibraries = new ConcurrentHashMap<>();
2729 }
2730 }
2731 }
2732 return libs;
2733 }
2734
2735 // -- Assertion management --
2736
2737 final Object assertionLock;
2738
2739 // The default toggle for assertion checking.
2740 // @GuardedBy("assertionLock")
2741 private boolean defaultAssertionStatus = false;
2742
2743 // Maps String packageName to Boolean package default assertion status Note
2744 // that the default package is placed under a null map key. If this field
2745 // is null then we are delegating assertion status queries to the VM, i.e.,
2746 // none of this ClassLoader's assertion status modification methods have
2747 // been invoked.
2748 // @GuardedBy("assertionLock")
2749 private Map<String, Boolean> packageAssertionStatus = null;
2750
2751 // Maps String fullyQualifiedClassName to Boolean assertionStatus If this
2752 // field is null then we are delegating assertion status queries to the VM,
2753 // i.e., none of this ClassLoader's assertion status modification methods
2754 // have been invoked.
2755 // @GuardedBy("assertionLock")
2756 Map<String, Boolean> classAssertionStatus = null;
2757
2758 /**
2759 * Sets the default assertion status for this class loader. This setting
2760 * determines whether classes loaded by this class loader and initialized
2761 * in the future will have assertions enabled or disabled by default.
2762 * This setting may be overridden on a per-package or per-class basis by
2763 * invoking {@link #setPackageAssertionStatus(String, boolean)} or {@link
2764 * #setClassAssertionStatus(String, boolean)}.
2765 *
2766 * @param enabled
2767 * {@code true} if classes loaded by this class loader will
2768 * henceforth have assertions enabled by default, {@code false}
2769 * if they will have assertions disabled by default.
2770 *
2771 * @since 1.4
2772 */
2773 public void setDefaultAssertionStatus(boolean enabled) {
2774 synchronized (assertionLock) {
2775 if (classAssertionStatus == null)
2776 initializeJavaAssertionMaps();
2777
2778 defaultAssertionStatus = enabled;
2779 }
2780 }
2781
2782 /**
2783 * Sets the package default assertion status for the named package. The
2784 * package default assertion status determines the assertion status for
2785 * classes initialized in the future that belong to the named package or
2786 * any of its "subpackages".
2787 *
2788 * <p> A subpackage of a package named p is any package whose name begins
2789 * with "{@code p.}". For example, {@code javax.swing.text} is a
2790 * subpackage of {@code javax.swing}, and both {@code java.util} and
2791 * {@code java.lang.reflect} are subpackages of {@code java}.
2792 *
2793 * <p> In the event that multiple package defaults apply to a given class,
2794 * the package default pertaining to the most specific package takes
2795 * precedence over the others. For example, if {@code javax.lang} and
2796 * {@code javax.lang.reflect} both have package defaults associated with
2797 * them, the latter package default applies to classes in
2798 * {@code javax.lang.reflect}.
2799 *
2800 * <p> Package defaults take precedence over the class loader's default
2801 * assertion status, and may be overridden on a per-class basis by invoking
2802 * {@link #setClassAssertionStatus(String, boolean)}. </p>
2803 *
2804 * @param packageName
2805 * The name of the package whose package default assertion status
2806 * is to be set. A {@code null} value indicates the unnamed
2807 * package that is "current"
2808 * (see section 7.4.2 of
2809 * <cite>The Java™ Language Specification</cite>.)
2810 *
2811 * @param enabled
2812 * {@code true} if classes loaded by this classloader and
2813 * belonging to the named package or any of its subpackages will
2814 * have assertions enabled by default, {@code false} if they will
2815 * have assertions disabled by default.
2816 *
2817 * @since 1.4
2818 */
2819 public void setPackageAssertionStatus(String packageName,
2820 boolean enabled) {
2821 synchronized (assertionLock) {
2822 if (packageAssertionStatus == null)
2823 initializeJavaAssertionMaps();
2824
2825 packageAssertionStatus.put(packageName, enabled);
2826 }
2827 }
2828
2829 /**
2830 * Sets the desired assertion status for the named top-level class in this
2831 * class loader and any nested classes contained therein. This setting
2832 * takes precedence over the class loader's default assertion status, and
2833 * over any applicable per-package default. This method has no effect if
2834 * the named class has already been initialized. (Once a class is
2835 * initialized, its assertion status cannot change.)
2836 *
2837 * <p> If the named class is not a top-level class, this invocation will
2838 * have no effect on the actual assertion status of any class. </p>
2839 *
2840 * @param className
2841 * The fully qualified class name of the top-level class whose
2842 * assertion status is to be set.
2843 *
2844 * @param enabled
2845 * {@code true} if the named class is to have assertions
2846 * enabled when (and if) it is initialized, {@code false} if the
2847 * class is to have assertions disabled.
2848 *
2849 * @since 1.4
2850 */
2851 public void setClassAssertionStatus(String className, boolean enabled) {
2852 synchronized (assertionLock) {
2853 if (classAssertionStatus == null)
2854 initializeJavaAssertionMaps();
2855
2856 classAssertionStatus.put(className, enabled);
2857 }
2858 }
2859
2860 /**
2861 * Sets the default assertion status for this class loader to
2862 * {@code false} and discards any package defaults or class assertion
2863 * status settings associated with the class loader. This method is
2864 * provided so that class loaders can be made to ignore any command line or
2865 * persistent assertion status settings and "start with a clean slate."
2866 *
2867 * @since 1.4
2868 */
2869 public void clearAssertionStatus() {
2870 /*
2871 * Whether or not "Java assertion maps" are initialized, set
2872 * them to empty maps, effectively ignoring any present settings.
2873 */
2874 synchronized (assertionLock) {
2875 classAssertionStatus = new HashMap<>();
2876 packageAssertionStatus = new HashMap<>();
2877 defaultAssertionStatus = false;
2878 }
2879 }
2880
2881 /**
2882 * Returns the assertion status that would be assigned to the specified
2883 * class if it were to be initialized at the time this method is invoked.
2884 * If the named class has had its assertion status set, the most recent
2885 * setting will be returned; otherwise, if any package default assertion
2886 * status pertains to this class, the most recent setting for the most
2887 * specific pertinent package default assertion status is returned;
2888 * otherwise, this class loader's default assertion status is returned.
2889 * </p>
2890 *
2891 * @param className
2892 * The fully qualified class name of the class whose desired
2893 * assertion status is being queried.
2894 *
2895 * @return The desired assertion status of the specified class.
2896 *
2897 * @see #setClassAssertionStatus(String, boolean)
2898 * @see #setPackageAssertionStatus(String, boolean)
2899 * @see #setDefaultAssertionStatus(boolean)
2900 *
2901 * @since 1.4
2902 */
2903 boolean desiredAssertionStatus(String className) {
2904 synchronized (assertionLock) {
2905 // assert classAssertionStatus != null;
2906 // assert packageAssertionStatus != null;
2907
2908 // Check for a class entry
2909 Boolean result = classAssertionStatus.get(className);
2910 if (result != null)
2911 return result.booleanValue();
2912
2913 // Check for most specific package entry
2914 int dotIndex = className.lastIndexOf('.');
2915 if (dotIndex < 0) { // default package
2916 result = packageAssertionStatus.get(null);
2917 if (result != null)
2918 return result.booleanValue();
2919 }
2920 while(dotIndex > 0) {
2921 className = className.substring(0, dotIndex);
2922 result = packageAssertionStatus.get(className);
2923 if (result != null)
2924 return result.booleanValue();
2925 dotIndex = className.lastIndexOf('.', dotIndex-1);
2926 }
2927
2928 // Return the classloader default
2929 return defaultAssertionStatus;
2930 }
2931 }
2932
2933 // Set up the assertions with information provided by the VM.
2934 // Note: Should only be called inside a synchronized block
2935 private void initializeJavaAssertionMaps() {
2936 // assert Thread.holdsLock(assertionLock);
2937
2938 classAssertionStatus = new HashMap<>();
2939 packageAssertionStatus = new HashMap<>();
2940 AssertionStatusDirectives directives = retrieveDirectives();
2941
2942 for(int i = 0; i < directives.classes.length; i++)
2943 classAssertionStatus.put(directives.classes[i],
2944 directives.classEnabled[i]);
2945
2946 for(int i = 0; i < directives.packages.length; i++)
2947 packageAssertionStatus.put(directives.packages[i],
2948 directives.packageEnabled[i]);
2949
2950 defaultAssertionStatus = directives.deflt;
2951 }
2952
2953 // Retrieves the assertion directives from the VM.
2954 private static native AssertionStatusDirectives retrieveDirectives();
2955
2956
2957 // -- Misc --
2958
2959 /**
2960 * Returns the ConcurrentHashMap used as a storage for ClassLoaderValue(s)
2961 * associated with this ClassLoader, creating it if it doesn't already exist.
2962 */
2963 ConcurrentHashMap<?, ?> createOrGetClassLoaderValueMap() {
2964 ConcurrentHashMap<?, ?> map = classLoaderValueMap;
2965 if (map == null) {
2966 map = new ConcurrentHashMap<>();
2967 boolean set = trySetObjectField("classLoaderValueMap", map);
2968 if (!set) {
2969 // beaten by someone else
2970 map = classLoaderValueMap;
2971 }
2972 }
2973 return map;
2974 }
2975
2976 // the storage for ClassLoaderValue(s) associated with this ClassLoader
2977 private volatile ConcurrentHashMap<?, ?> classLoaderValueMap;
2978
2979 /**
2980 * Attempts to atomically set a volatile field in this object. Returns
2981 * {@code true} if not beaten by another thread. Avoids the use of
2982 * AtomicReferenceFieldUpdater in this class.
2983 */
2984 private boolean trySetObjectField(String name, Object obj) {
2985 Unsafe unsafe = Unsafe.getUnsafe();
2986 Class<?> k = ClassLoader.class;
2987 long offset;
2988 offset = unsafe.objectFieldOffset(k, name);
2989 return unsafe.compareAndSetObject(this, offset, null, obj);
2990 }
2991 }
2992
2993 /*
2994 * A utility class that will enumerate over an array of enumerations.
2995 */
2996 final class CompoundEnumeration<E> implements Enumeration<E> {
2997 private final Enumeration<E>[] enums;
2998 private int index;
2999
3000 public CompoundEnumeration(Enumeration<E>[] enums) {
3001 this.enums = enums;
3002 }
3003
3004 private boolean next() {
3005 while (index < enums.length) {
3006 if (enums[index] != null && enums[index].hasMoreElements()) {
3007 return true;
3008 }
3009 index++;
3010 }
3011 return false;
3012 }
3013
3014 public boolean hasMoreElements() {
3015 return next();
3016 }
3017
3018 public E nextElement() {
3019 if (!next()) {
3020 throw new NoSuchElementException();
3021 }
3022 return enums[index].nextElement();
3023 }
3024 }