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