1 /*
2 * Copyright (c) 1994, 2010, 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 package java.lang;
26
27 import java.io.InputStream;
28 import java.io.IOException;
29 import java.io.File;
30 import java.lang.reflect.Constructor;
31 import java.lang.reflect.InvocationTargetException;
32 import java.net.MalformedURLException;
33 import java.net.URL;
34 import java.security.AccessController;
35 import java.security.AccessControlContext;
36 import java.security.CodeSource;
37 import java.security.Policy;
38 import java.security.PrivilegedAction;
39 import java.security.PrivilegedActionException;
40 import java.security.PrivilegedExceptionAction;
41 import java.security.ProtectionDomain;
42 import java.security.cert.Certificate;
43 import java.util.Collections;
44 import java.util.Enumeration;
45 import java.util.HashMap;
46 import java.util.HashSet;
47 import java.util.Set;
48 import java.util.Stack;
49 import java.util.Map;
50 import java.util.Vector;
51 import java.util.Hashtable;
52 import java.util.WeakHashMap;
53 import java.util.concurrent.ConcurrentHashMap;
54 import sun.misc.BootClassLoaderHook;
55 import sun.misc.ClassFileTransformer;
56 import sun.misc.CompoundEnumeration;
57 import sun.misc.Resource;
58 import sun.misc.URLClassPath;
59 import sun.misc.VM;
60 import sun.reflect.Reflection;
61 import sun.security.util.SecurityConstants;
62
63 /**
64 * A class loader is an object that is responsible for loading classes. The
65 * class <tt>ClassLoader</tt> is an abstract class. Given the <a
66 * href="#name">binary name</a> of a class, a class loader should attempt to
67 * locate or generate data that constitutes a definition for the class. A
68 * typical strategy is to transform the name into a file name and then read a
69 * "class file" of that name from a file system.
70 *
71 * <p> Every {@link Class <tt>Class</tt>} object contains a {@link
72 * Class#getClassLoader() reference} to the <tt>ClassLoader</tt> that defined
73 * it.
74 *
75 * <p> <tt>Class</tt> objects for array classes are not created by class
76 * loaders, but are created automatically as required by the Java runtime.
77 * The class loader for an array class, as returned by {@link
78 * Class#getClassLoader()} is the same as the class loader for its element
79 * type; if the element type is a primitive type, then the array class has no
80 * class loader.
81 *
82 * <p> Applications implement subclasses of <tt>ClassLoader</tt> in order to
83 * extend the manner in which the Java virtual machine dynamically loads
84 * classes.
85 *
86 * <p> Class loaders may typically be used by security managers to indicate
87 * security domains.
88 *
89 * <p> The <tt>ClassLoader</tt> class uses a delegation model to search for
90 * classes and resources. Each instance of <tt>ClassLoader</tt> has an
91 * associated parent class loader. When requested to find a class or
92 * resource, a <tt>ClassLoader</tt> instance will delegate the search for the
93 * class or resource to its parent class loader before attempting to find the
94 * class or resource itself. The virtual machine's built-in class loader,
95 * called the "bootstrap class loader", does not itself have a parent but may
96 * serve as the parent of a <tt>ClassLoader</tt> instance.
97 *
98 * <p> Class loaders that support concurrent loading of classes are known as
99 * <em>parallel capable</em> class loaders and are required to register
100 * themselves at their class initialization time by invoking the
101 * {@link
102 * #registerAsParallelCapable <tt>ClassLoader.registerAsParallelCapable</tt>}
103 * method. Note that the <tt>ClassLoader</tt> class is registered as parallel
104 * capable by default. However, its subclasses still need to register themselves
105 * if they are parallel capable. <br>
106 * In environments in which the delegation model is not strictly
107 * hierarchical, class loaders need to be parallel capable, otherwise class
108 * loading can lead to deadlocks because the loader lock is held for the
109 * duration of the class loading process (see {@link #loadClass
110 * <tt>loadClass</tt>} methods).
111 *
112 * <p> Normally, the Java virtual machine loads classes from the local file
113 * system in a platform-dependent manner. For example, on UNIX systems, the
114 * virtual machine loads classes from the directory defined by the
115 * <tt>CLASSPATH</tt> environment variable.
116 *
117 * <p> However, some classes may not originate from a file; they may originate
118 * from other sources, such as the network, or they could be constructed by an
119 * application. The method {@link #defineClass(String, byte[], int, int)
120 * <tt>defineClass</tt>} converts an array of bytes into an instance of class
121 * <tt>Class</tt>. Instances of this newly defined class can be created using
122 * {@link Class#newInstance <tt>Class.newInstance</tt>}.
123 *
124 * <p> The methods and constructors of objects created by a class loader may
125 * reference other classes. To determine the class(es) referred to, the Java
126 * virtual machine invokes the {@link #loadClass <tt>loadClass</tt>} method of
127 * the class loader that originally created the class.
128 *
129 * <p> For example, an application could create a network class loader to
130 * download class files from a server. Sample code might look like:
131 *
132 * <blockquote><pre>
133 * ClassLoader loader = new NetworkClassLoader(host, port);
134 * Object main = loader.loadClass("Main", true).newInstance();
135 * . . .
136 * </pre></blockquote>
137 *
138 * <p> The network class loader subclass must define the methods {@link
139 * #findClass <tt>findClass</tt>} and <tt>loadClassData</tt> to load a class
140 * from the network. Once it has downloaded the bytes that make up the class,
141 * it should use the method {@link #defineClass <tt>defineClass</tt>} to
142 * create a class instance. A sample implementation is:
143 *
144 * <blockquote><pre>
145 * class NetworkClassLoader extends ClassLoader {
146 * String host;
147 * int port;
148 *
149 * public Class findClass(String name) {
150 * byte[] b = loadClassData(name);
151 * return defineClass(name, b, 0, b.length);
152 * }
153 *
154 * private byte[] loadClassData(String name) {
155 * // load the class data from the connection
156 * . . .
157 * }
158 * }
159 * </pre></blockquote>
160 *
161 * <h4> <a name="name">Binary names</a> </h4>
162 *
163 * <p> Any class name provided as a {@link String} parameter to methods in
164 * <tt>ClassLoader</tt> must be a binary name as defined by the <a
165 * href="http://java.sun.com/docs/books/jls/">Java Language Specification</a>.
166 *
167 * <p> Examples of valid class names include:
168 * <blockquote><pre>
169 * "java.lang.String"
170 * "javax.swing.JSpinner$DefaultEditor"
171 * "java.security.KeyStore$Builder$FileBuilder$1"
172 * "java.net.URLClassLoader$3$1"
173 * </pre></blockquote>
174 *
175 * @see #resolveClass(Class)
176 * @since 1.0
177 */
178 public abstract class ClassLoader {
179
180 private static native void registerNatives();
181 static {
182 registerNatives();
183 }
184
185 // The parent class loader for delegation
186 // Note: VM hardcoded the offset of this field, thus all new fields
187 // must be added *after* it.
188 private final ClassLoader parent;
189
190 /**
191 * Encapsulates the set of parallel capable loader types.
192 */
193 private static class ParallelLoaders {
194 private ParallelLoaders() {}
195
196 // the set of parallel capable loader types
197 private static final Set<Class<? extends ClassLoader>> loaderTypes =
198 Collections.newSetFromMap(
199 new WeakHashMap<Class<? extends ClassLoader>, Boolean>());
200 static {
201 synchronized (loaderTypes) { loaderTypes.add(ClassLoader.class); }
202 }
203
204 /**
205 * Registers the given class loader type as parallel capabale.
206 * Returns {@code true} is successfully registered; {@code false} if
207 * loader's super class is not registered.
208 */
209 static boolean register(Class<? extends ClassLoader> c) {
210 synchronized (loaderTypes) {
211 if (loaderTypes.contains(c.getSuperclass())) {
212 // register the class loader as parallel capable
213 // if and only if all of its super classes are.
214 // Note: given current classloading sequence, if
215 // the immediate super class is parallel capable,
216 // all the super classes higher up must be too.
217 loaderTypes.add(c);
218 return true;
219 } else {
220 return false;
221 }
222 }
223 }
224
225 /**
226 * Returns {@code true} if the given class loader type is
227 * registered as parallel capable.
228 */
229 static boolean isRegistered(Class<? extends ClassLoader> c) {
230 synchronized (loaderTypes) {
231 return loaderTypes.contains(c);
232 }
233 }
234 }
235
236 // Maps class name to the corresponding lock object when the current
237 // class loader is parallel capable.
238 // Note: VM also uses this field to decide if the current class loader
239 // is parallel capable and the appropriate lock object for class loading.
240 private final ConcurrentHashMap<String, Object> parallelLockMap;
241
242 // Hashtable that maps packages to certs
243 private final Map <String, Certificate[]> package2certs;
244
245 // Shared among all packages with unsigned classes
246 private static final Certificate[] nocerts = new Certificate[0];
247
248 // The classes loaded by this class loader. The only purpose of this table
249 // is to keep the classes from being GC'ed until the loader is GC'ed.
250 private final Vector<Class<?>> classes = new Vector<Class<?>>();
251
252 // The "default" domain. Set as the default ProtectionDomain on newly
253 // created classes.
254 private final ProtectionDomain defaultDomain =
255 new ProtectionDomain(new CodeSource(null, (Certificate[]) null),
256 null, this, null);
257
258 // The initiating protection domains for all classes loaded by this loader
259 private final Set<ProtectionDomain> domains;
260
261 // Invoked by the VM to record every loaded class with this loader.
262 void addClass(Class c) {
263 classes.addElement(c);
264 }
265
266 // The packages defined in this class loader. Each package name is mapped
267 // to its corresponding Package object.
268 // @GuardedBy("itself")
269 private final HashMap<String, Package> packages =
270 new HashMap<String, Package>();
271
272 private static Void checkCreateClassLoader() {
273 SecurityManager security = System.getSecurityManager();
274 if (security != null) {
275 security.checkCreateClassLoader();
276 }
277 return null;
278 }
279
280 private ClassLoader(Void unused, ClassLoader parent) {
281 this.parent = parent;
282 if (ParallelLoaders.isRegistered(this.getClass())) {
283 parallelLockMap = new ConcurrentHashMap<String, Object>();
284 package2certs = new ConcurrentHashMap<String, Certificate[]>();
285 domains =
286 Collections.synchronizedSet(new HashSet<ProtectionDomain>());
287 assertionLock = new Object();
288 } else {
289 // no finer-grained lock; lock on the classloader instance
290 parallelLockMap = null;
291 package2certs = new Hashtable<String, Certificate[]>();
292 domains = new HashSet<ProtectionDomain>();
293 assertionLock = this;
294 }
295 }
296
297 /**
298 * Creates a new class loader using the specified parent class loader for
299 * delegation.
300 *
301 * <p> If there is a security manager, its {@link
302 * SecurityManager#checkCreateClassLoader()
303 * <tt>checkCreateClassLoader</tt>} method is invoked. This may result in
304 * a security exception. </p>
305 *
306 * @param parent
307 * The parent class loader
308 *
309 * @throws SecurityException
310 * If a security manager exists and its
311 * <tt>checkCreateClassLoader</tt> method doesn't allow creation
312 * of a new class loader.
313 *
314 * @since 1.2
315 */
316 protected ClassLoader(ClassLoader parent) {
317 this(checkCreateClassLoader(), parent);
318 }
319
320 /**
321 * Creates a new class loader using the <tt>ClassLoader</tt> returned by
322 * the method {@link #getSystemClassLoader()
323 * <tt>getSystemClassLoader()</tt>} as the parent class loader.
324 *
325 * <p> If there is a security manager, its {@link
326 * SecurityManager#checkCreateClassLoader()
327 * <tt>checkCreateClassLoader</tt>} method is invoked. This may result in
328 * a security exception. </p>
329 *
330 * @throws SecurityException
331 * If a security manager exists and its
332 * <tt>checkCreateClassLoader</tt> method doesn't allow creation
333 * of a new class loader.
334 */
335 protected ClassLoader() {
336 this(checkCreateClassLoader(), getSystemClassLoader());
337 }
338
339 // -- Class --
340
341 /**
342 * Loads the class with the specified <a href="#name">binary name</a>.
343 * This method searches for classes in the same manner as the {@link
344 * #loadClass(String, boolean)} method. It is invoked by the Java virtual
345 * machine to resolve class references. Invoking this method is equivalent
346 * to invoking {@link #loadClass(String, boolean) <tt>loadClass(name,
347 * false)</tt>}. </p>
348 *
349 * @param name
350 * The <a href="#name">binary name</a> of the class
351 *
352 * @return The resulting <tt>Class</tt> object
353 *
354 * @throws ClassNotFoundException
355 * If the class was not found
356 */
357 public Class<?> loadClass(String name) throws ClassNotFoundException {
358 return loadClass(name, false);
359 }
360
361 /**
362 * Loads the class with the specified <a href="#name">binary name</a>. The
363 * default implementation of this method searches for classes in the
364 * following order:
365 *
366 * <p><ol>
367 *
368 * <li><p> Invoke {@link #findLoadedClass(String)} to check if the class
369 * has already been loaded. </p></li>
370 *
371 * <li><p> Invoke the {@link #loadClass(String) <tt>loadClass</tt>} method
372 * on the parent class loader. If the parent is <tt>null</tt> the class
373 * loader built-in to the virtual machine is used, instead. </p></li>
374 *
375 * <li><p> Invoke the {@link #findClass(String)} method to find the
376 * class. </p></li>
377 *
378 * </ol>
379 *
380 * <p> If the class was found using the above steps, and the
381 * <tt>resolve</tt> flag is true, this method will then invoke the {@link
382 * #resolveClass(Class)} method on the resulting <tt>Class</tt> object.
383 *
384 * <p> Subclasses of <tt>ClassLoader</tt> are encouraged to override {@link
385 * #findClass(String)}, rather than this method. </p>
386 *
387 * <p> Unless overridden, this method synchronizes on the result of
388 * {@link #getClassLoadingLock <tt>getClassLoadingLock</tt>} method
389 * during the entire class loading process.
390 *
391 * @param name
392 * The <a href="#name">binary name</a> of the class
393 *
394 * @param resolve
395 * If <tt>true</tt> then resolve the class
396 *
397 * @return The resulting <tt>Class</tt> object
398 *
399 * @throws ClassNotFoundException
400 * If the class could not be found
401 */
402 protected Class<?> loadClass(String name, boolean resolve)
403 throws ClassNotFoundException
404 {
405 synchronized (getClassLoadingLock(name)) {
406 // First, check if the class has already been loaded
407 Class c = findLoadedClass(name);
408 if (c == null) {
409 long t0 = System.nanoTime();
410 try {
411 if (parent != null) {
412 c = parent.loadClass(name, false);
413 } else {
414 c = findBootstrapClassOrNull(name);
415 }
416 } catch (ClassNotFoundException e) {
417 // ClassNotFoundException thrown if class not found
418 // from the non-null parent class loader
419 }
420
421 if (c == null) {
422 // If still not found, then invoke findClass in order
423 // to find the class.
424 long t1 = System.nanoTime();
425 c = findClass(name);
426
427 // this is the defining class loader; record the stats
428 sun.misc.PerfCounter.getParentDelegationTime().addTime(t1 - t0);
429 sun.misc.PerfCounter.getFindClassTime().addElapsedTimeFrom(t1);
430 sun.misc.PerfCounter.getFindClasses().increment();
431 }
432 }
433 if (resolve) {
434 resolveClass(c);
435 }
436 return c;
437 }
438 }
439
440 /**
441 * Returns the lock object for class loading operations.
442 * For backward compatibility, the default implementation of this method
443 * behaves as follows. If this ClassLoader object is registered as
444 * parallel capable, the method returns a dedicated object associated
445 * with the specified class name. Otherwise, the method returns this
446 * ClassLoader object. </p>
447 *
448 * @param className
449 * The name of the to-be-loaded class
450 *
451 * @return the lock for class loading operations
452 *
453 * @throws NullPointerException
454 * If registered as parallel capable and <tt>className</tt> is null
455 *
456 * @see #loadClass(String, boolean)
457 *
458 * @since 1.7
459 */
460 protected Object getClassLoadingLock(String className) {
461 Object lock = this;
462 if (parallelLockMap != null) {
463 Object newLock = new Object();
464 lock = parallelLockMap.putIfAbsent(className, newLock);
465 if (lock == null) {
466 lock = newLock;
467 }
468 }
469 return lock;
470 }
471
472 // This method is invoked by the virtual machine to load a class.
473 private Class loadClassInternal(String name)
474 throws ClassNotFoundException
475 {
476 // For backward compatibility, explicitly lock on 'this' when
477 // the current class loader is not parallel capable.
478 if (parallelLockMap == null) {
479 synchronized (this) {
480 return loadClass(name);
481 }
482 } else {
483 return loadClass(name);
484 }
485 }
486
487 // Invoked by the VM after loading class with this loader.
488 private void checkPackageAccess(Class cls, ProtectionDomain pd) {
489 final SecurityManager sm = System.getSecurityManager();
490 if (sm != null) {
491 final String name = cls.getName();
492 final int i = name.lastIndexOf('.');
493 if (i != -1) {
494 AccessController.doPrivileged(new PrivilegedAction<Void>() {
495 public Void run() {
496 sm.checkPackageAccess(name.substring(0, i));
497 return null;
498 }
499 }, new AccessControlContext(new ProtectionDomain[] {pd}));
500 }
501 }
502 domains.add(pd);
503 }
504
505 /**
506 * Finds the class with the specified <a href="#name">binary name</a>.
507 * This method should be overridden by class loader implementations that
508 * follow the delegation model for loading classes, and will be invoked by
509 * the {@link #loadClass <tt>loadClass</tt>} method after checking the
510 * parent class loader for the requested class. The default implementation
511 * throws a <tt>ClassNotFoundException</tt>. </p>
512 *
513 * @param name
514 * The <a href="#name">binary name</a> of the class
515 *
516 * @return The resulting <tt>Class</tt> object
517 *
518 * @throws ClassNotFoundException
519 * If the class could not be found
520 *
521 * @since 1.2
522 */
523 protected Class<?> findClass(String name) throws ClassNotFoundException {
524 throw new ClassNotFoundException(name);
525 }
526
527 /**
528 * Converts an array of bytes into an instance of class <tt>Class</tt>.
529 * Before the <tt>Class</tt> can be used it must be resolved. This method
530 * is deprecated in favor of the version that takes a <a
531 * href="#name">binary name</a> as its first argument, and is more secure.
532 *
533 * @param b
534 * The bytes that make up the class data. The bytes in positions
535 * <tt>off</tt> through <tt>off+len-1</tt> should have the format
536 * of a valid class file as defined by the <a
537 * href="http://java.sun.com/docs/books/vmspec/">Java Virtual
538 * Machine Specification</a>.
539 *
540 * @param off
541 * The start offset in <tt>b</tt> of the class data
542 *
543 * @param len
544 * The length of the class data
545 *
546 * @return The <tt>Class</tt> object that was created from the specified
547 * class data
548 *
549 * @throws ClassFormatError
550 * If the data did not contain a valid class
551 *
552 * @throws IndexOutOfBoundsException
553 * If either <tt>off</tt> or <tt>len</tt> is negative, or if
554 * <tt>off+len</tt> is greater than <tt>b.length</tt>.
555 *
556 * @throws SecurityException
557 * If an attempt is made to add this class to a package that
558 * contains classes that were signed by a different set of
559 * certificates than this class, or if an attempt is made
560 * to define a class in a package with a fully-qualified name
561 * that starts with "{@code java.}".
562 *
563 * @see #loadClass(String, boolean)
564 * @see #resolveClass(Class)
565 *
566 * @deprecated Replaced by {@link #defineClass(String, byte[], int, int)
567 * defineClass(String, byte[], int, int)}
568 */
569 @Deprecated
570 protected final Class<?> defineClass(byte[] b, int off, int len)
571 throws ClassFormatError
572 {
573 return defineClass(null, b, off, len, null);
574 }
575
576 /**
577 * Converts an array of bytes into an instance of class <tt>Class</tt>.
578 * Before the <tt>Class</tt> can be used it must be resolved.
579 *
580 * <p> This method assigns a default {@link java.security.ProtectionDomain
581 * <tt>ProtectionDomain</tt>} to the newly defined class. The
582 * <tt>ProtectionDomain</tt> is effectively granted the same set of
583 * permissions returned when {@link
584 * java.security.Policy#getPermissions(java.security.CodeSource)
585 * <tt>Policy.getPolicy().getPermissions(new CodeSource(null, null))</tt>}
586 * is invoked. The default domain is created on the first invocation of
587 * {@link #defineClass(String, byte[], int, int) <tt>defineClass</tt>},
588 * and re-used on subsequent invocations.
589 *
590 * <p> To assign a specific <tt>ProtectionDomain</tt> to the class, use
591 * the {@link #defineClass(String, byte[], int, int,
592 * java.security.ProtectionDomain) <tt>defineClass</tt>} method that takes a
593 * <tt>ProtectionDomain</tt> as one of its arguments. </p>
594 *
595 * @param name
596 * The expected <a href="#name">binary name</a> of the class, or
597 * <tt>null</tt> if not known
598 *
599 * @param b
600 * The bytes that make up the class data. The bytes in positions
601 * <tt>off</tt> through <tt>off+len-1</tt> should have the format
602 * of a valid class file as defined by the <a
603 * href="http://java.sun.com/docs/books/vmspec/">Java Virtual
604 * Machine Specification</a>.
605 *
606 * @param off
607 * The start offset in <tt>b</tt> of the class data
608 *
609 * @param len
610 * The length of the class data
611 *
612 * @return The <tt>Class</tt> object that was created from the specified
613 * class data.
614 *
615 * @throws ClassFormatError
616 * If the data did not contain a valid class
617 *
618 * @throws IndexOutOfBoundsException
619 * If either <tt>off</tt> or <tt>len</tt> is negative, or if
620 * <tt>off+len</tt> is greater than <tt>b.length</tt>.
621 *
622 * @throws SecurityException
623 * If an attempt is made to add this class to a package that
624 * contains classes that were signed by a different set of
625 * certificates than this class (which is unsigned), or if
626 * <tt>name</tt> begins with "<tt>java.</tt>".
627 *
628 * @see #loadClass(String, boolean)
629 * @see #resolveClass(Class)
630 * @see java.security.CodeSource
631 * @see java.security.SecureClassLoader
632 *
633 * @since 1.1
634 */
635 protected final Class<?> defineClass(String name, byte[] b, int off, int len)
636 throws ClassFormatError
637 {
638 return defineClass(name, b, off, len, null);
639 }
640
641 /* Determine protection domain, and check that:
642 - not define java.* class,
643 - signer of this class matches signers for the rest of the classes in
644 package.
645 */
646 private ProtectionDomain preDefineClass(String name,
647 ProtectionDomain pd)
648 {
649 if (!checkName(name))
650 throw new NoClassDefFoundError("IllegalName: " + name);
651
652 if ((name != null) && name.startsWith("java.")) {
653 throw new SecurityException
654 ("Prohibited package name: " +
655 name.substring(0, name.lastIndexOf('.')));
656 }
657 if (pd == null) {
658 pd = defaultDomain;
659 }
660
661 if (name != null) checkCerts(name, pd.getCodeSource());
662
663 return pd;
664 }
665
666 private String defineClassSourceLocation(ProtectionDomain pd)
667 {
668 CodeSource cs = pd.getCodeSource();
669 String source = null;
670 if (cs != null && cs.getLocation() != null) {
671 source = cs.getLocation().toString();
672 }
673 return source;
674 }
675
676 private Class defineTransformedClass(String name, byte[] b, int off, int len,
677 ProtectionDomain pd,
678 ClassFormatError cfe, String source)
679 throws ClassFormatError
680 {
681 // Class format error - try to transform the bytecode and
682 // define the class again
683 //
684 ClassFileTransformer[] transformers =
685 ClassFileTransformer.getTransformers();
686 Class c = null;
687
688 if (transformers != null) {
689 for (ClassFileTransformer transformer : transformers) {
690 try {
691 // Transform byte code using transformer
692 byte[] tb = transformer.transform(b, off, len);
693 c = defineClass1(name, tb, 0, tb.length,
694 pd, source);
695 break;
696 } catch (ClassFormatError cfe2) {
697 // If ClassFormatError occurs, try next transformer
698 }
699 }
700 }
701
702 // Rethrow original ClassFormatError if unable to transform
703 // bytecode to well-formed
704 //
705 if (c == null)
706 throw cfe;
707
708 return c;
709 }
710
711 private void postDefineClass(Class c, ProtectionDomain pd)
712 {
713 if (pd.getCodeSource() != null) {
714 Certificate certs[] = pd.getCodeSource().getCertificates();
715 if (certs != null)
716 setSigners(c, certs);
717 }
718 }
719
720 /**
721 * Converts an array of bytes into an instance of class <tt>Class</tt>,
722 * with an optional <tt>ProtectionDomain</tt>. If the domain is
723 * <tt>null</tt>, then a default domain will be assigned to the class as
724 * specified in the documentation for {@link #defineClass(String, byte[],
725 * int, int)}. Before the class can be used it must be resolved.
726 *
727 * <p> The first class defined in a package determines the exact set of
728 * certificates that all subsequent classes defined in that package must
729 * contain. The set of certificates for a class is obtained from the
730 * {@link java.security.CodeSource <tt>CodeSource</tt>} within the
731 * <tt>ProtectionDomain</tt> of the class. Any classes added to that
732 * package must contain the same set of certificates or a
733 * <tt>SecurityException</tt> will be thrown. Note that if
734 * <tt>name</tt> is <tt>null</tt>, this check is not performed.
735 * You should always pass in the <a href="#name">binary name</a> of the
736 * class you are defining as well as the bytes. This ensures that the
737 * class you are defining is indeed the class you think it is.
738 *
739 * <p> The specified <tt>name</tt> cannot begin with "<tt>java.</tt>", since
740 * all classes in the "<tt>java.*</tt> packages can only be defined by the
741 * bootstrap class loader. If <tt>name</tt> is not <tt>null</tt>, it
742 * must be equal to the <a href="#name">binary name</a> of the class
743 * specified by the byte array "<tt>b</tt>", otherwise a {@link
744 * <tt>NoClassDefFoundError</tt>} will be thrown. </p>
745 *
746 * @param name
747 * The expected <a href="#name">binary name</a> of the class, or
748 * <tt>null</tt> if not known
749 *
750 * @param b
751 * The bytes that make up the class data. The bytes in positions
752 * <tt>off</tt> through <tt>off+len-1</tt> should have the format
753 * of a valid class file as defined by the <a
754 * href="http://java.sun.com/docs/books/vmspec/">Java Virtual
755 * Machine Specification</a>.
756 *
757 * @param off
758 * The start offset in <tt>b</tt> of the class data
759 *
760 * @param len
761 * The length of the class data
762 *
763 * @param protectionDomain
764 * The ProtectionDomain of the class
765 *
766 * @return The <tt>Class</tt> object created from the data,
767 * and optional <tt>ProtectionDomain</tt>.
768 *
769 * @throws ClassFormatError
770 * If the data did not contain a valid class
771 *
772 * @throws NoClassDefFoundError
773 * If <tt>name</tt> is not equal to the <a href="#name">binary
774 * name</a> of the class specified by <tt>b</tt>
775 *
776 * @throws IndexOutOfBoundsException
777 * If either <tt>off</tt> or <tt>len</tt> is negative, or if
778 * <tt>off+len</tt> is greater than <tt>b.length</tt>.
779 *
780 * @throws SecurityException
781 * If an attempt is made to add this class to a package that
782 * contains classes that were signed by a different set of
783 * certificates than this class, or if <tt>name</tt> begins with
784 * "<tt>java.</tt>".
785 */
786 protected final Class<?> defineClass(String name, byte[] b, int off, int len,
787 ProtectionDomain protectionDomain)
788 throws ClassFormatError
789 {
790 protectionDomain = preDefineClass(name, protectionDomain);
791
792 Class c = null;
793 String source = defineClassSourceLocation(protectionDomain);
794
795 try {
796 c = defineClass1(name, b, off, len, protectionDomain, source);
797 } catch (ClassFormatError cfe) {
798 c = defineTransformedClass(name, b, off, len, protectionDomain, cfe,
799 source);
800 }
801
802 postDefineClass(c, protectionDomain);
803 return c;
804 }
805
806 /**
807 * Converts a {@link java.nio.ByteBuffer <tt>ByteBuffer</tt>}
808 * into an instance of class <tt>Class</tt>,
809 * with an optional <tt>ProtectionDomain</tt>. If the domain is
810 * <tt>null</tt>, then a default domain will be assigned to the class as
811 * specified in the documentation for {@link #defineClass(String, byte[],
812 * int, int)}. Before the class can be used it must be resolved.
813 *
814 * <p>The rules about the first class defined in a package determining the
815 * set of certificates for the package, and the restrictions on class names
816 * are identical to those specified in the documentation for {@link
817 * #defineClass(String, byte[], int, int, ProtectionDomain)}.
818 *
819 * <p> An invocation of this method of the form
820 * <i>cl</i><tt>.defineClass(</tt><i>name</i><tt>,</tt>
821 * <i>bBuffer</i><tt>,</tt> <i>pd</i><tt>)</tt> yields exactly the same
822 * result as the statements
823 *
824 * <blockquote><tt>
825 * ...<br>
826 * byte[] temp = new byte[</tt><i>bBuffer</i><tt>.{@link
827 * java.nio.ByteBuffer#remaining remaining}()];<br>
828 * </tt><i>bBuffer</i><tt>.{@link java.nio.ByteBuffer#get(byte[])
829 * get}(temp);<br>
830 * return {@link #defineClass(String, byte[], int, int, ProtectionDomain)
831 * </tt><i>cl</i><tt>.defineClass}(</tt><i>name</i><tt>, temp, 0,
832 * temp.length, </tt><i>pd</i><tt>);<br>
833 * </tt></blockquote>
834 *
835 * @param name
836 * The expected <a href="#name">binary name</a>. of the class, or
837 * <tt>null</tt> if not known
838 *
839 * @param b
840 * The bytes that make up the class data. The bytes from positions
841 * <tt>b.position()</tt> through <tt>b.position() + b.limit() -1
842 * </tt> should have the format of a valid class file as defined by
843 * the <a href="http://java.sun.com/docs/books/vmspec/">Java Virtual
844 * Machine Specification</a>.
845 *
846 * @param protectionDomain
847 * The ProtectionDomain of the class, or <tt>null</tt>.
848 *
849 * @return The <tt>Class</tt> object created from the data,
850 * and optional <tt>ProtectionDomain</tt>.
851 *
852 * @throws ClassFormatError
853 * If the data did not contain a valid class.
854 *
855 * @throws NoClassDefFoundError
856 * If <tt>name</tt> is not equal to the <a href="#name">binary
857 * name</a> of the class specified by <tt>b</tt>
858 *
859 * @throws SecurityException
860 * If an attempt is made to add this class to a package that
861 * contains classes that were signed by a different set of
862 * certificates than this class, or if <tt>name</tt> begins with
863 * "<tt>java.</tt>".
864 *
865 * @see #defineClass(String, byte[], int, int, ProtectionDomain)
866 *
867 * @since 1.5
868 */
869 protected final Class<?> defineClass(String name, java.nio.ByteBuffer b,
870 ProtectionDomain protectionDomain)
871 throws ClassFormatError
872 {
873 int len = b.remaining();
874
875 // Use byte[] if not a direct ByteBufer:
876 if (!b.isDirect()) {
877 if (b.hasArray()) {
878 return defineClass(name, b.array(),
879 b.position() + b.arrayOffset(), len,
880 protectionDomain);
881 } else {
882 // no array, or read-only array
883 byte[] tb = new byte[len];
884 b.get(tb); // get bytes out of byte buffer.
885 return defineClass(name, tb, 0, len, protectionDomain);
886 }
887 }
888
889 protectionDomain = preDefineClass(name, protectionDomain);
890
891 Class c = null;
892 String source = defineClassSourceLocation(protectionDomain);
893
894 try {
895 c = defineClass2(name, b, b.position(), len, protectionDomain,
896 source);
897 } catch (ClassFormatError cfe) {
898 byte[] tb = new byte[len];
899 b.get(tb); // get bytes out of byte buffer.
900 c = defineTransformedClass(name, tb, 0, len, protectionDomain, cfe,
901 source);
902 }
903
904 postDefineClass(c, protectionDomain);
905 return c;
906 }
907
908 private native Class defineClass0(String name, byte[] b, int off, int len,
909 ProtectionDomain pd);
910
911 private native Class defineClass1(String name, byte[] b, int off, int len,
912 ProtectionDomain pd, String source);
913
914 private native Class defineClass2(String name, java.nio.ByteBuffer b,
915 int off, int len, ProtectionDomain pd,
916 String source);
917
918 // true if the name is null or has the potential to be a valid binary name
919 private boolean checkName(String name) {
920 if ((name == null) || (name.length() == 0))
921 return true;
922 if ((name.indexOf('/') != -1)
923 || (!VM.allowArraySyntax() && (name.charAt(0) == '[')))
924 return false;
925 return true;
926 }
927
928 private void checkCerts(String name, CodeSource cs) {
929 int i = name.lastIndexOf('.');
930 String pname = (i == -1) ? "" : name.substring(0, i);
931
932 Certificate[] certs = null;
933 if (cs != null) {
934 certs = cs.getCertificates();
935 }
936 Certificate[] pcerts = null;
937 if (parallelLockMap == null) {
938 synchronized (this) {
939 pcerts = package2certs.get(pname);
940 if (pcerts == null) {
941 package2certs.put(pname, (certs == null? nocerts:certs));
942 }
943 }
944 } else {
945 pcerts = ((ConcurrentHashMap<String, Certificate[]>)package2certs).
946 putIfAbsent(pname, (certs == null? nocerts:certs));
947 }
948 if (pcerts != null && !compareCerts(pcerts, certs)) {
949 throw new SecurityException("class \""+ name +
950 "\"'s signer information does not match signer information of other classes in the same package");
951 }
952 }
953
954 /**
955 * check to make sure the certs for the new class (certs) are the same as
956 * the certs for the first class inserted in the package (pcerts)
957 */
958 private boolean compareCerts(Certificate[] pcerts,
959 Certificate[] certs)
960 {
961 // certs can be null, indicating no certs.
962 if ((certs == null) || (certs.length == 0)) {
963 return pcerts.length == 0;
964 }
965
966 // the length must be the same at this point
967 if (certs.length != pcerts.length)
968 return false;
969
970 // go through and make sure all the certs in one array
971 // are in the other and vice-versa.
972 boolean match;
973 for (int i = 0; i < certs.length; i++) {
974 match = false;
975 for (int j = 0; j < pcerts.length; j++) {
976 if (certs[i].equals(pcerts[j])) {
977 match = true;
978 break;
979 }
980 }
981 if (!match) return false;
982 }
983
984 // now do the same for pcerts
985 for (int i = 0; i < pcerts.length; i++) {
986 match = false;
987 for (int j = 0; j < certs.length; j++) {
988 if (pcerts[i].equals(certs[j])) {
989 match = true;
990 break;
991 }
992 }
993 if (!match) return false;
994 }
995
996 return true;
997 }
998
999 /**
1000 * Links the specified class. This (misleadingly named) method may be
1001 * used by a class loader to link a class. If the class <tt>c</tt> has
1002 * already been linked, then this method simply returns. Otherwise, the
1003 * class is linked as described in the "Execution" chapter of the <a
1004 * href="http://java.sun.com/docs/books/jls/">Java Language
1005 * Specification</a>.
1006 * </p>
1007 *
1008 * @param c
1009 * The class to link
1010 *
1011 * @throws NullPointerException
1012 * If <tt>c</tt> is <tt>null</tt>.
1013 *
1014 * @see #defineClass(String, byte[], int, int)
1015 */
1016 protected final void resolveClass(Class<?> c) {
1017 resolveClass0(c);
1018 }
1019
1020 private native void resolveClass0(Class c);
1021
1022 /**
1023 * Finds a class with the specified <a href="#name">binary name</a>,
1024 * loading it if necessary.
1025 *
1026 * <p> This method loads the class through the system class loader (see
1027 * {@link #getSystemClassLoader()}). The <tt>Class</tt> object returned
1028 * might have more than one <tt>ClassLoader</tt> associated with it.
1029 * Subclasses of <tt>ClassLoader</tt> need not usually invoke this method,
1030 * because most class loaders need to override just {@link
1031 * #findClass(String)}. </p>
1032 *
1033 * @param name
1034 * The <a href="#name">binary name</a> of the class
1035 *
1036 * @return The <tt>Class</tt> object for the specified <tt>name</tt>
1037 *
1038 * @throws ClassNotFoundException
1039 * If the class could not be found
1040 *
1041 * @see #ClassLoader(ClassLoader)
1042 * @see #getParent()
1043 */
1044 protected final Class<?> findSystemClass(String name)
1045 throws ClassNotFoundException
1046 {
1047 ClassLoader system = getSystemClassLoader();
1048 if (system == null) {
1049 if (!checkName(name))
1050 throw new ClassNotFoundException(name);
1051 Class cls = findBootstrapClass(name);
1052 if (cls == null) {
1053 throw new ClassNotFoundException(name);
1054 }
1055 return cls;
1056 }
1057 return system.loadClass(name);
1058 }
1059
1060 /**
1061 * Returns a class loaded by the bootstrap class loader;
1062 * or return null if not found.
1063 */
1064 private Class findBootstrapClassOrNull(String name)
1065 {
1066 if (!checkName(name)) return null;
1067
1068 return findBootstrapClass(name);
1069 }
1070
1071 // return null if not found
1072 private native Class findBootstrapClass(String name);
1073
1074 /**
1075 * Returns the class with the given <a href="#name">binary name</a> if this
1076 * loader has been recorded by the Java virtual machine as an initiating
1077 * loader of a class with that <a href="#name">binary name</a>. Otherwise
1078 * <tt>null</tt> is returned. </p>
1079 *
1080 * @param name
1081 * The <a href="#name">binary name</a> of the class
1082 *
1083 * @return The <tt>Class</tt> object, or <tt>null</tt> if the class has
1084 * not been loaded
1085 *
1086 * @since 1.1
1087 */
1088 protected final Class<?> findLoadedClass(String name) {
1089 if (!checkName(name))
1090 return null;
1091 return findLoadedClass0(name);
1092 }
1093
1094 private native final Class findLoadedClass0(String name);
1095
1096 /**
1097 * Sets the signers of a class. This should be invoked after defining a
1098 * class. </p>
1099 *
1100 * @param c
1101 * The <tt>Class</tt> object
1102 *
1103 * @param signers
1104 * The signers for the class
1105 *
1106 * @since 1.1
1107 */
1108 protected final void setSigners(Class<?> c, Object[] signers) {
1109 c.setSigners(signers);
1110 }
1111
1112
1113 // -- Resource --
1114
1115 /**
1116 * Finds the resource with the given name. A resource is some data
1117 * (images, audio, text, etc) that can be accessed by class code in a way
1118 * that is independent of the location of the code.
1119 *
1120 * <p> The name of a resource is a '<tt>/</tt>'-separated path name that
1121 * identifies the resource.
1122 *
1123 * <p> This method will first search the parent class loader for the
1124 * resource; if the parent is <tt>null</tt> the path of the class loader
1125 * built-in to the virtual machine is searched. That failing, this method
1126 * will invoke {@link #findResource(String)} to find the resource. </p>
1127 *
1128 * @param name
1129 * The resource name
1130 *
1131 * @return A <tt>URL</tt> object for reading the resource, or
1132 * <tt>null</tt> if the resource could not be found or the invoker
1133 * doesn't have adequate privileges to get the resource.
1134 *
1135 * @since 1.1
1136 */
1137 public URL getResource(String name) {
1138 URL url;
1139 if (parent != null) {
1140 url = parent.getResource(name);
1141 } else {
1142 url = getBootstrapResource(name);
1143 }
1144 if (url == null) {
1145 url = findResource(name);
1146 }
1147 return url;
1148 }
1149
1150 /**
1151 * Finds all the resources with the given name. A resource is some data
1152 * (images, audio, text, etc) that can be accessed by class code in a way
1153 * that is independent of the location of the code.
1154 *
1155 * <p>The name of a resource is a <tt>/</tt>-separated path name that
1156 * identifies the resource.
1157 *
1158 * <p> The search order is described in the documentation for {@link
1159 * #getResource(String)}. </p>
1160 *
1161 * @param name
1162 * The resource name
1163 *
1164 * @return An enumeration of {@link java.net.URL <tt>URL</tt>} objects for
1165 * the resource. If no resources could be found, the enumeration
1166 * will be empty. Resources that the class loader doesn't have
1167 * access to will not be in the enumeration.
1168 *
1169 * @throws IOException
1170 * If I/O errors occur
1171 *
1172 * @see #findResources(String)
1173 *
1174 * @since 1.2
1175 */
1176 public Enumeration<URL> getResources(String name) throws IOException {
1177 Enumeration[] tmp = new Enumeration[2];
1178 if (parent != null) {
1179 tmp[0] = parent.getResources(name);
1180 } else {
1181 tmp[0] = getBootstrapResources(name);
1182 }
1183 tmp[1] = findResources(name);
1184
1185 return new CompoundEnumeration<URL>(tmp);
1186 }
1187
1188 /**
1189 * Finds the resource with the given name. Class loader implementations
1190 * should override this method to specify where to find resources. </p>
1191 *
1192 * @param name
1193 * The resource name
1194 *
1195 * @return A <tt>URL</tt> object for reading the resource, or
1196 * <tt>null</tt> if the resource could not be found
1197 *
1198 * @since 1.2
1199 */
1200 protected URL findResource(String name) {
1201 return null;
1202 }
1203
1204 /**
1205 * Returns an enumeration of {@link java.net.URL <tt>URL</tt>} objects
1206 * representing all the resources with the given name. Class loader
1207 * implementations should override this method to specify where to load
1208 * resources from. </p>
1209 *
1210 * @param name
1211 * The resource name
1212 *
1213 * @return An enumeration of {@link java.net.URL <tt>URL</tt>} objects for
1214 * the resources
1215 *
1216 * @throws IOException
1217 * If I/O errors occur
1218 *
1219 * @since 1.2
1220 */
1221 protected Enumeration<URL> findResources(String name) throws IOException {
1222 return java.util.Collections.emptyEnumeration();
1223 }
1224
1225 // index 0: java.lang.ClassLoader.class
1226 // index 1: the immediate caller of index 0.
1227 // index 2: the immediate caller of index 1.
1228 private static native Class<? extends ClassLoader> getCaller(int index);
1229
1230 /**
1231 * Registers the caller as parallel capable.</p>
1232 * The registration succeeds if and only if all of the following
1233 * conditions are met: <br>
1234 * 1. no instance of the caller has been created</p>
1235 * 2. all of the super classes (except class Object) of the caller are
1236 * registered as parallel capable</p>
1237 * Note that once a class loader is registered as parallel capable, there
1238 * is no way to change it back. </p>
1239 *
1240 * @return true if the caller is successfully registered as
1241 * parallel capable and false if otherwise.
1242 *
1243 * @since 1.7
1244 */
1245 protected static boolean registerAsParallelCapable() {
1246 return ParallelLoaders.register(getCaller(1));
1247 }
1248
1249 /**
1250 * Find a resource of the specified name from the search path used to load
1251 * classes. This method locates the resource through the system class
1252 * loader (see {@link #getSystemClassLoader()}). </p>
1253 *
1254 * @param name
1255 * The resource name
1256 *
1257 * @return A {@link java.net.URL <tt>URL</tt>} object for reading the
1258 * resource, or <tt>null</tt> if the resource could not be found
1259 *
1260 * @since 1.1
1261 */
1262 public static URL getSystemResource(String name) {
1263 ClassLoader system = getSystemClassLoader();
1264 if (system == null) {
1265 return getBootstrapResource(name);
1266 }
1267 return system.getResource(name);
1268 }
1269
1270 /**
1271 * Finds all resources of the specified name from the search path used to
1272 * load classes. The resources thus found are returned as an
1273 * {@link java.util.Enumeration <tt>Enumeration</tt>} of {@link
1274 * java.net.URL <tt>URL</tt>} objects.
1275 *
1276 * <p> The search order is described in the documentation for {@link
1277 * #getSystemResource(String)}. </p>
1278 *
1279 * @param name
1280 * The resource name
1281 *
1282 * @return An enumeration of resource {@link java.net.URL <tt>URL</tt>}
1283 * objects
1284 *
1285 * @throws IOException
1286 * If I/O errors occur
1287
1288 * @since 1.2
1289 */
1290 public static Enumeration<URL> getSystemResources(String name)
1291 throws IOException
1292 {
1293 ClassLoader system = getSystemClassLoader();
1294 if (system == null) {
1295 return getBootstrapResources(name);
1296 }
1297 return system.getResources(name);
1298 }
1299
1300 /**
1301 * Find resources from the VM's built-in classloader.
1302 */
1303 private static URL getBootstrapResource(String name) {
1304 BootClassLoaderHook.preLoadResource(name);
1305 URLClassPath ucp = getBootstrapClassPath();
1306 Resource res = ucp.getResource(name);
1307 return res != null ? res.getURL() : null;
1308 }
1309
1310 /**
1311 * Find resources from the VM's built-in classloader.
1312 */
1313 private static Enumeration<URL> getBootstrapResources(String name)
1314 throws IOException
1315 {
1316 final Enumeration<Resource> e =
1317 getBootstrapClassPath().getResources(name);
1318 return new Enumeration<URL> () {
1319 public URL nextElement() {
1320 return e.nextElement().getURL();
1321 }
1322 public boolean hasMoreElements() {
1323 return e.hasMoreElements();
1324 }
1325 };
1326 }
1327
1328 // Returns the URLClassPath that is used for finding system resources.
1329 static URLClassPath getBootstrapClassPath() {
1330 return sun.misc.Launcher.getBootstrapClassPath();
1331 }
1332
1333
1334 /**
1335 * Returns an input stream for reading the specified resource.
1336 *
1337 * <p> The search order is described in the documentation for {@link
1338 * #getResource(String)}. </p>
1339 *
1340 * @param name
1341 * The resource name
1342 *
1343 * @return An input stream for reading the resource, or <tt>null</tt>
1344 * if the resource could not be found
1345 *
1346 * @since 1.1
1347 */
1348 public InputStream getResourceAsStream(String name) {
1349 URL url = getResource(name);
1350 try {
1351 return url != null ? url.openStream() : null;
1352 } catch (IOException e) {
1353 return null;
1354 }
1355 }
1356
1357 /**
1358 * Open for reading, a resource of the specified name from the search path
1359 * used to load classes. This method locates the resource through the
1360 * system class loader (see {@link #getSystemClassLoader()}). </p>
1361 *
1362 * @param name
1363 * The resource name
1364 *
1365 * @return An input stream for reading the resource, or <tt>null</tt>
1366 * if the resource could not be found
1367 *
1368 * @since 1.1
1369 */
1370 public static InputStream getSystemResourceAsStream(String name) {
1371 URL url = getSystemResource(name);
1372 try {
1373 return url != null ? url.openStream() : null;
1374 } catch (IOException e) {
1375 return null;
1376 }
1377 }
1378
1379
1380 // -- Hierarchy --
1381
1382 /**
1383 * Returns the parent class loader for delegation. Some implementations may
1384 * use <tt>null</tt> to represent the bootstrap class loader. This method
1385 * will return <tt>null</tt> in such implementations if this class loader's
1386 * parent is the bootstrap class loader.
1387 *
1388 * <p> If a security manager is present, and the invoker's class loader is
1389 * not <tt>null</tt> and is not an ancestor of this class loader, then this
1390 * method invokes the security manager's {@link
1391 * SecurityManager#checkPermission(java.security.Permission)
1392 * <tt>checkPermission</tt>} method with a {@link
1393 * RuntimePermission#RuntimePermission(String)
1394 * <tt>RuntimePermission("getClassLoader")</tt>} permission to verify
1395 * access to the parent class loader is permitted. If not, a
1396 * <tt>SecurityException</tt> will be thrown. </p>
1397 *
1398 * @return The parent <tt>ClassLoader</tt>
1399 *
1400 * @throws SecurityException
1401 * If a security manager exists and its <tt>checkPermission</tt>
1402 * method doesn't allow access to this class loader's parent class
1403 * loader.
1404 *
1405 * @since 1.2
1406 */
1407 public final ClassLoader getParent() {
1408 if (parent == null)
1409 return null;
1410 SecurityManager sm = System.getSecurityManager();
1411 if (sm != null) {
1412 ClassLoader ccl = getCallerClassLoader();
1413 if (ccl != null && !isAncestor(ccl)) {
1414 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
1415 }
1416 }
1417 return parent;
1418 }
1419
1420 /**
1421 * Returns the system class loader for delegation. This is the default
1422 * delegation parent for new <tt>ClassLoader</tt> instances, and is
1423 * typically the class loader used to start the application.
1424 *
1425 * <p> This method is first invoked early in the runtime's startup
1426 * sequence, at which point it creates the system class loader and sets it
1427 * as the context class loader of the invoking <tt>Thread</tt>.
1428 *
1429 * <p> The default system class loader is an implementation-dependent
1430 * instance of this class.
1431 *
1432 * <p> If the system property "<tt>java.system.class.loader</tt>" is defined
1433 * when this method is first invoked then the value of that property is
1434 * taken to be the name of a class that will be returned as the system
1435 * class loader. The class is loaded using the default system class loader
1436 * and must define a public constructor that takes a single parameter of
1437 * type <tt>ClassLoader</tt> which is used as the delegation parent. An
1438 * instance is then created using this constructor with the default system
1439 * class loader as the parameter. The resulting class loader is defined
1440 * to be the system class loader.
1441 *
1442 * <p> If a security manager is present, and the invoker's class loader is
1443 * not <tt>null</tt> and the invoker's class loader is not the same as or
1444 * an ancestor of the system class loader, then this method invokes the
1445 * security manager's {@link
1446 * SecurityManager#checkPermission(java.security.Permission)
1447 * <tt>checkPermission</tt>} method with a {@link
1448 * RuntimePermission#RuntimePermission(String)
1449 * <tt>RuntimePermission("getClassLoader")</tt>} permission to verify
1450 * access to the system class loader. If not, a
1451 * <tt>SecurityException</tt> will be thrown. </p>
1452 *
1453 * @return The system <tt>ClassLoader</tt> for delegation, or
1454 * <tt>null</tt> if none
1455 *
1456 * @throws SecurityException
1457 * If a security manager exists and its <tt>checkPermission</tt>
1458 * method doesn't allow access to the system class loader.
1459 *
1460 * @throws IllegalStateException
1461 * If invoked recursively during the construction of the class
1462 * loader specified by the "<tt>java.system.class.loader</tt>"
1463 * property.
1464 *
1465 * @throws Error
1466 * If the system property "<tt>java.system.class.loader</tt>"
1467 * is defined but the named class could not be loaded, the
1468 * provider class does not define the required constructor, or an
1469 * exception is thrown by that constructor when it is invoked. The
1470 * underlying cause of the error can be retrieved via the
1471 * {@link Throwable#getCause()} method.
1472 *
1473 * @revised 1.4
1474 */
1475 public static ClassLoader getSystemClassLoader() {
1476 initSystemClassLoader();
1477 if (scl == null) {
1478 return null;
1479 }
1480 SecurityManager sm = System.getSecurityManager();
1481 if (sm != null) {
1482 ClassLoader ccl = getCallerClassLoader();
1483 if (ccl != null && ccl != scl && !scl.isAncestor(ccl)) {
1484 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
1485 }
1486 }
1487 return scl;
1488 }
1489
1490 private static synchronized void initSystemClassLoader() {
1491 if (!sclSet) {
1492 if (scl != null)
1493 throw new IllegalStateException("recursive invocation");
1494 sun.misc.Launcher l = sun.misc.Launcher.getLauncher();
1495 if (l != null) {
1496 Throwable oops = null;
1497 scl = l.getClassLoader();
1498 try {
1499 scl = AccessController.doPrivileged(
1500 new SystemClassLoaderAction(scl));
1501 } catch (PrivilegedActionException pae) {
1502 oops = pae.getCause();
1503 if (oops instanceof InvocationTargetException) {
1504 oops = oops.getCause();
1505 }
1506 }
1507 if (oops != null) {
1508 if (oops instanceof Error) {
1509 throw (Error) oops;
1510 } else {
1511 // wrap the exception
1512 throw new Error(oops);
1513 }
1514 }
1515 }
1516 sclSet = true;
1517 }
1518 }
1519
1520 // Returns true if the specified class loader can be found in this class
1521 // loader's delegation chain.
1522 boolean isAncestor(ClassLoader cl) {
1523 ClassLoader acl = this;
1524 do {
1525 acl = acl.parent;
1526 if (cl == acl) {
1527 return true;
1528 }
1529 } while (acl != null);
1530 return false;
1531 }
1532
1533 // Returns the invoker's class loader, or null if none.
1534 // NOTE: This must always be invoked when there is exactly one intervening
1535 // frame from the core libraries on the stack between this method's
1536 // invocation and the desired invoker.
1537 static ClassLoader getCallerClassLoader() {
1538 // NOTE use of more generic Reflection.getCallerClass()
1539 Class caller = Reflection.getCallerClass(3);
1540 // This can be null if the VM is requesting it
1541 if (caller == null) {
1542 return null;
1543 }
1544 // Circumvent security check since this is package-private
1545 return caller.getClassLoader0();
1546 }
1547
1548 // The class loader for the system
1549 // @GuardedBy("ClassLoader.class")
1550 private static ClassLoader scl;
1551
1552 // Set to true once the system class loader has been set
1553 // @GuardedBy("ClassLoader.class")
1554 private static boolean sclSet;
1555
1556
1557 // -- Package --
1558
1559 /**
1560 * Defines a package by name in this <tt>ClassLoader</tt>. This allows
1561 * class loaders to define the packages for their classes. Packages must
1562 * be created before the class is defined, and package names must be
1563 * unique within a class loader and cannot be redefined or changed once
1564 * created. </p>
1565 *
1566 * @param name
1567 * The package name
1568 *
1569 * @param specTitle
1570 * The specification title
1571 *
1572 * @param specVersion
1573 * The specification version
1574 *
1575 * @param specVendor
1576 * The specification vendor
1577 *
1578 * @param implTitle
1579 * The implementation title
1580 *
1581 * @param implVersion
1582 * The implementation version
1583 *
1584 * @param implVendor
1585 * The implementation vendor
1586 *
1587 * @param sealBase
1588 * If not <tt>null</tt>, then this package is sealed with
1589 * respect to the given code source {@link java.net.URL
1590 * <tt>URL</tt>} object. Otherwise, the package is not sealed.
1591 *
1592 * @return The newly defined <tt>Package</tt> object
1593 *
1594 * @throws IllegalArgumentException
1595 * If package name duplicates an existing package either in this
1596 * class loader or one of its ancestors
1597 *
1598 * @since 1.2
1599 */
1600 protected Package definePackage(String name, String specTitle,
1601 String specVersion, String specVendor,
1602 String implTitle, String implVersion,
1603 String implVendor, URL sealBase)
1604 throws IllegalArgumentException
1605 {
1606 synchronized (packages) {
1607 Package pkg = getPackage(name);
1608 if (pkg != null) {
1609 throw new IllegalArgumentException(name);
1610 }
1611 pkg = new Package(name, specTitle, specVersion, specVendor,
1612 implTitle, implVersion, implVendor,
1613 sealBase, this);
1614 packages.put(name, pkg);
1615 return pkg;
1616 }
1617 }
1618
1619 /**
1620 * Returns a <tt>Package</tt> that has been defined by this class loader
1621 * or any of its ancestors. </p>
1622 *
1623 * @param name
1624 * The package name
1625 *
1626 * @return The <tt>Package</tt> corresponding to the given name, or
1627 * <tt>null</tt> if not found
1628 *
1629 * @since 1.2
1630 */
1631 protected Package getPackage(String name) {
1632 synchronized (packages) {
1633 Package pkg = packages.get(name);
1634 if (pkg == null) {
1635 if (parent != null) {
1636 pkg = parent.getPackage(name);
1637 } else {
1638 pkg = Package.getSystemPackage(name);
1639 }
1640 if (pkg != null) {
1641 packages.put(name, pkg);
1642 }
1643 }
1644 return pkg;
1645 }
1646 }
1647
1648 /**
1649 * Returns all of the <tt>Packages</tt> defined by this class loader and
1650 * its ancestors. </p>
1651 *
1652 * @return The array of <tt>Package</tt> objects defined by this
1653 * <tt>ClassLoader</tt>
1654 *
1655 * @since 1.2
1656 */
1657 protected Package[] getPackages() {
1658 Map<String, Package> map;
1659 synchronized (packages) {
1660 map = new HashMap<String, Package>(packages);
1661 }
1662 Package[] pkgs;
1663 if (parent != null) {
1664 pkgs = parent.getPackages();
1665 } else {
1666 pkgs = Package.getSystemPackages();
1667 }
1668 if (pkgs != null) {
1669 for (int i = 0; i < pkgs.length; i++) {
1670 String pkgName = pkgs[i].getName();
1671 if (map.get(pkgName) == null) {
1672 map.put(pkgName, pkgs[i]);
1673 }
1674 }
1675 }
1676 return map.values().toArray(new Package[map.size()]);
1677 }
1678
1679
1680 // -- Native library access --
1681
1682 /**
1683 * Returns the absolute path name of a native library. The VM invokes this
1684 * method to locate the native libraries that belong to classes loaded with
1685 * this class loader. If this method returns <tt>null</tt>, the VM
1686 * searches the library along the path specified as the
1687 * "<tt>java.library.path</tt>" property. </p>
1688 *
1689 * @param libname
1690 * The library name
1691 *
1692 * @return The absolute path of the native library
1693 *
1694 * @see System#loadLibrary(String)
1695 * @see System#mapLibraryName(String)
1696 *
1697 * @since 1.2
1698 */
1699 protected String findLibrary(String libname) {
1700 return null;
1701 }
1702
1703 /**
1704 * The inner class NativeLibrary denotes a loaded native library instance.
1705 * Every classloader contains a vector of loaded native libraries in the
1706 * private field <tt>nativeLibraries</tt>. The native libraries loaded
1707 * into the system are entered into the <tt>systemNativeLibraries</tt>
1708 * vector.
1709 *
1710 * <p> Every native library requires a particular version of JNI. This is
1711 * denoted by the private <tt>jniVersion</tt> field. This field is set by
1712 * the VM when it loads the library, and used by the VM to pass the correct
1713 * version of JNI to the native methods. </p>
1714 *
1715 * @see ClassLoader
1716 * @since 1.2
1717 */
1718 static class NativeLibrary {
1719 // opaque handle to native library, used in native code.
1720 long handle;
1721 // the version of JNI environment the native library requires.
1722 private int jniVersion;
1723 // the class from which the library is loaded, also indicates
1724 // the loader this native library belongs.
1725 private Class fromClass;
1726 // the canonicalized name of the native library.
1727 String name;
1728
1729 native void load(String name);
1730 native long find(String name);
1731 native void unload();
1732
1733 public NativeLibrary(Class fromClass, String name) {
1734 this.name = name;
1735 this.fromClass = fromClass;
1736 }
1737
1738 protected void finalize() {
1739 synchronized (loadedLibraryNames) {
1740 if (fromClass.getClassLoader() != null && handle != 0) {
1741 /* remove the native library name */
1742 int size = loadedLibraryNames.size();
1743 for (int i = 0; i < size; i++) {
1744 if (name.equals(loadedLibraryNames.elementAt(i))) {
1745 loadedLibraryNames.removeElementAt(i);
1746 break;
1747 }
1748 }
1749 /* unload the library. */
1750 ClassLoader.nativeLibraryContext.push(this);
1751 try {
1752 unload();
1753 } finally {
1754 ClassLoader.nativeLibraryContext.pop();
1755 }
1756 }
1757 }
1758 }
1759 // Invoked in the VM to determine the context class in
1760 // JNI_Load/JNI_Unload
1761 static Class getFromClass() {
1762 return ClassLoader.nativeLibraryContext.peek().fromClass;
1763 }
1764 }
1765
1766 // All native library names we've loaded.
1767 private static Vector<String> loadedLibraryNames
1768 = new Vector<String>();
1769
1770 // Native libraries belonging to system classes.
1771 private static Vector<NativeLibrary> systemNativeLibraries
1772 = new Vector<NativeLibrary>();
1773
1774 // Native libraries associated with the class loader.
1775 private Vector<NativeLibrary> nativeLibraries
1776 = new Vector<NativeLibrary>();
1777
1778 // native libraries being loaded/unloaded.
1779 private static Stack<NativeLibrary> nativeLibraryContext
1780 = new Stack<NativeLibrary>();
1781
1782 // The paths searched for libraries
1783 private static String usr_paths[];
1784 private static String sys_paths[];
1785
1786 private static String[] initializePath(String propname) {
1787 String ldpath = System.getProperty(propname, "");
1788 String ps = File.pathSeparator;
1789 int ldlen = ldpath.length();
1790 int i, j, n;
1791 // Count the separators in the path
1792 i = ldpath.indexOf(ps);
1793 n = 0;
1794 while (i >= 0) {
1795 n++;
1796 i = ldpath.indexOf(ps, i + 1);
1797 }
1798
1799 // allocate the array of paths - n :'s = n + 1 path elements
1800 String[] paths = new String[n + 1];
1801
1802 // Fill the array with paths from the ldpath
1803 n = i = 0;
1804 j = ldpath.indexOf(ps);
1805 while (j >= 0) {
1806 if (j - i > 0) {
1807 paths[n++] = ldpath.substring(i, j);
1808 } else if (j - i == 0) {
1809 paths[n++] = ".";
1810 }
1811 i = j + 1;
1812 j = ldpath.indexOf(ps, i);
1813 }
1814 paths[n] = ldpath.substring(i, ldlen);
1815 return paths;
1816 }
1817
1818 // Invoked in the java.lang.Runtime class to implement load and loadLibrary.
1819 static void loadLibrary(Class fromClass, String name,
1820 boolean isAbsolute) {
1821 BootClassLoaderHook.preLoadLibrary(name);
1822 ClassLoader loader =
1823 (fromClass == null) ? null : fromClass.getClassLoader();
1824 if (sys_paths == null) {
1825 usr_paths = initializePath("java.library.path");
1826 sys_paths = initializePath("sun.boot.library.path");
1827 }
1828 if (isAbsolute) {
1829 if (loadLibrary0(fromClass, new File(name))) {
1830 return;
1831 }
1832 throw new UnsatisfiedLinkError("Can't load library: " + name);
1833 }
1834 if (loader != null) {
1835 String libfilename = loader.findLibrary(name);
1836 if (libfilename != null) {
1837 File libfile = new File(libfilename);
1838 if (!libfile.isAbsolute()) {
1839 throw new UnsatisfiedLinkError(
1840 "ClassLoader.findLibrary failed to return an absolute path: " + libfilename);
1841 }
1842 if (loadLibrary0(fromClass, libfile)) {
1843 return;
1844 }
1845 throw new UnsatisfiedLinkError("Can't load " + libfilename);
1846 }
1847 }
1848 for (int i = 0 ; i < sys_paths.length ; i++) {
1849 File libfile = new File(sys_paths[i], System.mapLibraryName(name));
1850 if (loadLibrary0(fromClass, libfile)) {
1851 return;
1852 }
1853 }
1854 if (loader != null) {
1855 for (int i = 0 ; i < usr_paths.length ; i++) {
1856 File libfile = new File(usr_paths[i],
1857 System.mapLibraryName(name));
1858 if (loadLibrary0(fromClass, libfile)) {
1859 return;
1860 }
1861 }
1862 }
1863 // Oops, it failed
1864 throw new UnsatisfiedLinkError("no " + name + " in java.library.path");
1865 }
1866
1867 private static boolean loadLibrary0(Class fromClass, final File file) {
1868 boolean exists = AccessController.doPrivileged(
1869 new PrivilegedAction<Object>() {
1870 public Object run() {
1871 return file.exists() ? Boolean.TRUE : null;
1872 }})
1873 != null;
1874 if (!exists) {
1875 return false;
1876 }
1877 String name;
1878 try {
1879 name = file.getCanonicalPath();
1880 } catch (IOException e) {
1881 return false;
1882 }
1883 ClassLoader loader =
1884 (fromClass == null) ? null : fromClass.getClassLoader();
1885 Vector<NativeLibrary> libs =
1886 loader != null ? loader.nativeLibraries : systemNativeLibraries;
1887 synchronized (libs) {
1888 int size = libs.size();
1889 for (int i = 0; i < size; i++) {
1890 NativeLibrary lib = libs.elementAt(i);
1891 if (name.equals(lib.name)) {
1892 return true;
1893 }
1894 }
1895
1896 synchronized (loadedLibraryNames) {
1897 if (loadedLibraryNames.contains(name)) {
1898 throw new UnsatisfiedLinkError
1899 ("Native Library " +
1900 name +
1901 " already loaded in another classloader");
1902 }
1903 /* If the library is being loaded (must be by the same thread,
1904 * because Runtime.load and Runtime.loadLibrary are
1905 * synchronous). The reason is can occur is that the JNI_OnLoad
1906 * function can cause another loadLibrary invocation.
1907 *
1908 * Thus we can use a static stack to hold the list of libraries
1909 * we are loading.
1910 *
1911 * If there is a pending load operation for the library, we
1912 * immediately return success; otherwise, we raise
1913 * UnsatisfiedLinkError.
1914 */
1915 int n = nativeLibraryContext.size();
1916 for (int i = 0; i < n; i++) {
1917 NativeLibrary lib = nativeLibraryContext.elementAt(i);
1918 if (name.equals(lib.name)) {
1919 if (loader == lib.fromClass.getClassLoader()) {
1920 return true;
1921 } else {
1922 throw new UnsatisfiedLinkError
1923 ("Native Library " +
1924 name +
1925 " is being loaded in another classloader");
1926 }
1927 }
1928 }
1929 NativeLibrary lib = new NativeLibrary(fromClass, name);
1930 nativeLibraryContext.push(lib);
1931 try {
1932 lib.load(name);
1933 } finally {
1934 nativeLibraryContext.pop();
1935 }
1936 if (lib.handle != 0) {
1937 loadedLibraryNames.addElement(name);
1938 libs.addElement(lib);
1939 return true;
1940 }
1941 return false;
1942 }
1943 }
1944 }
1945
1946 // Invoked in the VM class linking code.
1947 static long findNative(ClassLoader loader, String name) {
1948 Vector<NativeLibrary> libs =
1949 loader != null ? loader.nativeLibraries : systemNativeLibraries;
1950 synchronized (libs) {
1951 int size = libs.size();
1952 for (int i = 0; i < size; i++) {
1953 NativeLibrary lib = libs.elementAt(i);
1954 long entry = lib.find(name);
1955 if (entry != 0)
1956 return entry;
1957 }
1958 }
1959 return 0;
1960 }
1961
1962
1963 // -- Assertion management --
1964
1965 final Object assertionLock;
1966
1967 // The default toggle for assertion checking.
1968 // @GuardedBy("assertionLock")
1969 private boolean defaultAssertionStatus = false;
1970
1971 // Maps String packageName to Boolean package default assertion status Note
1972 // that the default package is placed under a null map key. If this field
1973 // is null then we are delegating assertion status queries to the VM, i.e.,
1974 // none of this ClassLoader's assertion status modification methods have
1975 // been invoked.
1976 // @GuardedBy("assertionLock")
1977 private Map<String, Boolean> packageAssertionStatus = null;
1978
1979 // Maps String fullyQualifiedClassName to Boolean assertionStatus If this
1980 // field is null then we are delegating assertion status queries to the VM,
1981 // i.e., none of this ClassLoader's assertion status modification methods
1982 // have been invoked.
1983 // @GuardedBy("assertionLock")
1984 Map<String, Boolean> classAssertionStatus = null;
1985
1986 /**
1987 * Sets the default assertion status for this class loader. This setting
1988 * determines whether classes loaded by this class loader and initialized
1989 * in the future will have assertions enabled or disabled by default.
1990 * This setting may be overridden on a per-package or per-class basis by
1991 * invoking {@link #setPackageAssertionStatus(String, boolean)} or {@link
1992 * #setClassAssertionStatus(String, boolean)}. </p>
1993 *
1994 * @param enabled
1995 * <tt>true</tt> if classes loaded by this class loader will
1996 * henceforth have assertions enabled by default, <tt>false</tt>
1997 * if they will have assertions disabled by default.
1998 *
1999 * @since 1.4
2000 */
2001 public void setDefaultAssertionStatus(boolean enabled) {
2002 synchronized (assertionLock) {
2003 if (classAssertionStatus == null)
2004 initializeJavaAssertionMaps();
2005
2006 defaultAssertionStatus = enabled;
2007 }
2008 }
2009
2010 /**
2011 * Sets the package default assertion status for the named package. The
2012 * package default assertion status determines the assertion status for
2013 * classes initialized in the future that belong to the named package or
2014 * any of its "subpackages".
2015 *
2016 * <p> A subpackage of a package named p is any package whose name begins
2017 * with "<tt>p.</tt>". For example, <tt>javax.swing.text</tt> is a
2018 * subpackage of <tt>javax.swing</tt>, and both <tt>java.util</tt> and
2019 * <tt>java.lang.reflect</tt> are subpackages of <tt>java</tt>.
2020 *
2021 * <p> In the event that multiple package defaults apply to a given class,
2022 * the package default pertaining to the most specific package takes
2023 * precedence over the others. For example, if <tt>javax.lang</tt> and
2024 * <tt>javax.lang.reflect</tt> both have package defaults associated with
2025 * them, the latter package default applies to classes in
2026 * <tt>javax.lang.reflect</tt>.
2027 *
2028 * <p> Package defaults take precedence over the class loader's default
2029 * assertion status, and may be overridden on a per-class basis by invoking
2030 * {@link #setClassAssertionStatus(String, boolean)}. </p>
2031 *
2032 * @param packageName
2033 * The name of the package whose package default assertion status
2034 * is to be set. A <tt>null</tt> value indicates the unnamed
2035 * package that is "current"
2036 * (<a href="http://java.sun.com/docs/books/jls/">Java Language
2037 * Specification</a>, section 7.4.2).
2038 *
2039 * @param enabled
2040 * <tt>true</tt> if classes loaded by this classloader and
2041 * belonging to the named package or any of its subpackages will
2042 * have assertions enabled by default, <tt>false</tt> if they will
2043 * have assertions disabled by default.
2044 *
2045 * @since 1.4
2046 */
2047 public void setPackageAssertionStatus(String packageName,
2048 boolean enabled) {
2049 synchronized (assertionLock) {
2050 if (packageAssertionStatus == null)
2051 initializeJavaAssertionMaps();
2052
2053 packageAssertionStatus.put(packageName, enabled);
2054 }
2055 }
2056
2057 /**
2058 * Sets the desired assertion status for the named top-level class in this
2059 * class loader and any nested classes contained therein. This setting
2060 * takes precedence over the class loader's default assertion status, and
2061 * over any applicable per-package default. This method has no effect if
2062 * the named class has already been initialized. (Once a class is
2063 * initialized, its assertion status cannot change.)
2064 *
2065 * <p> If the named class is not a top-level class, this invocation will
2066 * have no effect on the actual assertion status of any class. </p>
2067 *
2068 * @param className
2069 * The fully qualified class name of the top-level class whose
2070 * assertion status is to be set.
2071 *
2072 * @param enabled
2073 * <tt>true</tt> if the named class is to have assertions
2074 * enabled when (and if) it is initialized, <tt>false</tt> if the
2075 * class is to have assertions disabled.
2076 *
2077 * @since 1.4
2078 */
2079 public void setClassAssertionStatus(String className, boolean enabled) {
2080 synchronized (assertionLock) {
2081 if (classAssertionStatus == null)
2082 initializeJavaAssertionMaps();
2083
2084 classAssertionStatus.put(className, enabled);
2085 }
2086 }
2087
2088 /**
2089 * Sets the default assertion status for this class loader to
2090 * <tt>false</tt> and discards any package defaults or class assertion
2091 * status settings associated with the class loader. This method is
2092 * provided so that class loaders can be made to ignore any command line or
2093 * persistent assertion status settings and "start with a clean slate."
2094 * </p>
2095 *
2096 * @since 1.4
2097 */
2098 public void clearAssertionStatus() {
2099 /*
2100 * Whether or not "Java assertion maps" are initialized, set
2101 * them to empty maps, effectively ignoring any present settings.
2102 */
2103 synchronized (assertionLock) {
2104 classAssertionStatus = new HashMap<String, Boolean>();
2105 packageAssertionStatus = new HashMap<String, Boolean>();
2106 defaultAssertionStatus = false;
2107 }
2108 }
2109
2110 /**
2111 * Returns the assertion status that would be assigned to the specified
2112 * class if it were to be initialized at the time this method is invoked.
2113 * If the named class has had its assertion status set, the most recent
2114 * setting will be returned; otherwise, if any package default assertion
2115 * status pertains to this class, the most recent setting for the most
2116 * specific pertinent package default assertion status is returned;
2117 * otherwise, this class loader's default assertion status is returned.
2118 * </p>
2119 *
2120 * @param className
2121 * The fully qualified class name of the class whose desired
2122 * assertion status is being queried.
2123 *
2124 * @return The desired assertion status of the specified class.
2125 *
2126 * @see #setClassAssertionStatus(String, boolean)
2127 * @see #setPackageAssertionStatus(String, boolean)
2128 * @see #setDefaultAssertionStatus(boolean)
2129 *
2130 * @since 1.4
2131 */
2132 boolean desiredAssertionStatus(String className) {
2133 synchronized (assertionLock) {
2134 // assert classAssertionStatus != null;
2135 // assert packageAssertionStatus != null;
2136
2137 // Check for a class entry
2138 Boolean result = classAssertionStatus.get(className);
2139 if (result != null)
2140 return result.booleanValue();
2141
2142 // Check for most specific package entry
2143 int dotIndex = className.lastIndexOf(".");
2144 if (dotIndex < 0) { // default package
2145 result = packageAssertionStatus.get(null);
2146 if (result != null)
2147 return result.booleanValue();
2148 }
2149 while(dotIndex > 0) {
2150 className = className.substring(0, dotIndex);
2151 result = packageAssertionStatus.get(className);
2152 if (result != null)
2153 return result.booleanValue();
2154 dotIndex = className.lastIndexOf(".", dotIndex-1);
2155 }
2156
2157 // Return the classloader default
2158 return defaultAssertionStatus;
2159 }
2160 }
2161
2162 // Set up the assertions with information provided by the VM.
2163 // Note: Should only be called inside a synchronized block
2164 private void initializeJavaAssertionMaps() {
2165 // assert Thread.holdsLock(assertionLock);
2166
2167 classAssertionStatus = new HashMap<String, Boolean>();
2168 packageAssertionStatus = new HashMap<String, Boolean>();
2169 AssertionStatusDirectives directives = retrieveDirectives();
2170
2171 for(int i = 0; i < directives.classes.length; i++)
2172 classAssertionStatus.put(directives.classes[i],
2173 directives.classEnabled[i]);
2174
2175 for(int i = 0; i < directives.packages.length; i++)
2176 packageAssertionStatus.put(directives.packages[i],
2177 directives.packageEnabled[i]);
2178
2179 defaultAssertionStatus = directives.deflt;
2180 }
2181
2182 // Retrieves the assertion directives from the VM.
2183 private static native AssertionStatusDirectives retrieveDirectives();
2184 }
2185
2186
2187 class SystemClassLoaderAction
2188 implements PrivilegedExceptionAction<ClassLoader> {
2189 private ClassLoader parent;
2190
2191 SystemClassLoaderAction(ClassLoader parent) {
2192 this.parent = parent;
2193 }
2194
2195 public ClassLoader run() throws Exception {
2196 String cls = System.getProperty("java.system.class.loader");
2197 if (cls == null) {
2198 return parent;
2199 }
2200
2201 Constructor ctor = Class.forName(cls, true, parent)
2202 .getDeclaredConstructor(new Class[] { ClassLoader.class });
2203 ClassLoader sys = (ClassLoader) ctor.newInstance(
2204 new Object[] { parent });
2205 Thread.currentThread().setContextClassLoader(sys);
2206 return sys;
2207 }
2208 }