1 /*
2 * Copyright (c) 2013, 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.CompoundEnumeration;
55 import sun.misc.Resource;
56 import sun.misc.URLClassPath;
57 import sun.misc.VM;
58 import sun.reflect.CallerSensitive;
59 import sun.reflect.Reflection;
60 import sun.reflect.misc.ReflectUtil;
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 * <h3> <a name="name">Binary names</a> </h3>
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
165 * <cite>The Java™ Language Specification</cite>.
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 * {@code Class} objects for array classes are not created by {@code ClassLoader};
176 * use the {@link Class#forName} method instead.
177 *
178 * @jls 13.1 The Form of a Binary
179 * @see #resolveClass(Class)
180 * @since 1.0
181 */
182 public abstract class ClassLoader {
183
184 private static native void registerNatives();
185 static {
186 registerNatives();
187 }
188
189 // The parent class loader for delegation
190 // Note: VM hardcoded the offset of this field, thus all new fields
191 // must be added *after* it.
192 private final ClassLoader parent;
193
194 /**
195 * Encapsulates the set of parallel capable loader types.
196 */
197 private static class ParallelLoaders {
198 private ParallelLoaders() {}
199
200 // the set of parallel capable loader types
201 private static final Set<Class<? extends ClassLoader>> loaderTypes =
202 Collections.newSetFromMap(new WeakHashMap<>());
203 static {
204 synchronized (loaderTypes) { loaderTypes.add(ClassLoader.class); }
205 }
206
207 /**
208 * Registers the given class loader type as parallel capable.
209 * Returns {@code true} is successfully registered; {@code false} if
210 * loader's super class is not registered.
211 */
212 static boolean register(Class<? extends ClassLoader> c) {
213 synchronized (loaderTypes) {
214 if (loaderTypes.contains(c.getSuperclass())) {
215 // register the class loader as parallel capable
216 // if and only if all of its super classes are.
217 // Note: given current classloading sequence, if
218 // the immediate super class is parallel capable,
219 // all the super classes higher up must be too.
220 loaderTypes.add(c);
221 return true;
222 } else {
223 return false;
224 }
225 }
226 }
227
228 /**
229 * Returns {@code true} if the given class loader type is
230 * registered as parallel capable.
231 */
232 static boolean isRegistered(Class<? extends ClassLoader> c) {
233 synchronized (loaderTypes) {
234 return loaderTypes.contains(c);
235 }
236 }
237 }
238
239 // Maps class name to the corresponding lock object when the current
240 // class loader is parallel capable.
241 // Note: VM also uses this field to decide if the current class loader
242 // is parallel capable and the appropriate lock object for class loading.
243 private final ConcurrentHashMap<String, Object> parallelLockMap;
244
245 // Hashtable that maps packages to certs
246 private final Map <String, Certificate[]> package2certs;
247
248 // Shared among all packages with unsigned classes
249 private static final Certificate[] nocerts = new Certificate[0];
250
251 // The classes loaded by this class loader. The only purpose of this table
252 // is to keep the classes from being GC'ed until the loader is GC'ed.
253 private final Vector<Class<?>> classes = new Vector<>();
254
255 // The "default" domain. Set as the default ProtectionDomain on newly
256 // created classes.
257 private final ProtectionDomain defaultDomain =
258 new ProtectionDomain(new CodeSource(null, (Certificate[]) null),
259 null, this, null);
260
261 // The initiating protection domains for all classes loaded by this loader
262 private final Set<ProtectionDomain> domains;
263
264 // Invoked by the VM to record every loaded class with this loader.
265 void addClass(Class<?> c) {
266 classes.addElement(c);
267 }
268
269 // The packages defined in this class loader. Each package name is mapped
270 // to its corresponding Package object.
271 // @GuardedBy("itself")
272 private final HashMap<String, Package> packages = new HashMap<>();
273
274 private static Void checkCreateClassLoader() {
275 SecurityManager security = System.getSecurityManager();
276 if (security != null) {
277 security.checkCreateClassLoader();
278 }
279 return null;
280 }
281
282 private ClassLoader(Void unused, ClassLoader parent) {
283 this.parent = parent;
284 if (ParallelLoaders.isRegistered(this.getClass())) {
285 parallelLockMap = new ConcurrentHashMap<>();
286 package2certs = new ConcurrentHashMap<>();
287 domains = Collections.synchronizedSet(new HashSet<>());
288 assertionLock = new Object();
289 } else {
290 // no finer-grained lock; lock on the classloader instance
291 parallelLockMap = null;
292 package2certs = new Hashtable<>();
293 domains = new HashSet<>();
294 assertionLock = this;
295 }
296 }
297
298 /**
299 * Creates a new class loader using the specified parent class loader for
300 * delegation.
301 *
302 * <p> If there is a security manager, its {@link
303 * SecurityManager#checkCreateClassLoader()
304 * <tt>checkCreateClassLoader</tt>} method is invoked. This may result in
305 * a security exception. </p>
306 *
307 * @param parent
308 * The parent class loader
309 *
310 * @throws SecurityException
311 * If a security manager exists and its
312 * <tt>checkCreateClassLoader</tt> method doesn't allow creation
313 * of a new class loader.
314 *
315 * @since 1.2
316 */
317 protected ClassLoader(ClassLoader parent) {
318 this(checkCreateClassLoader(), parent);
319 }
320
321 /**
322 * Creates a new class loader using the <tt>ClassLoader</tt> returned by
323 * the method {@link #getSystemClassLoader()
324 * <tt>getSystemClassLoader()</tt>} as the parent class loader.
325 *
326 * <p> If there is a security manager, its {@link
327 * SecurityManager#checkCreateClassLoader()
328 * <tt>checkCreateClassLoader</tt>} method is invoked. This may result in
329 * a security exception. </p>
330 *
331 * @throws SecurityException
332 * If a security manager exists and its
333 * <tt>checkCreateClassLoader</tt> method doesn't allow creation
334 * of a new class loader.
335 */
336 protected ClassLoader() {
337 this(checkCreateClassLoader(), getSystemClassLoader());
338 }
339
340 // -- Class --
341
342 /**
343 * Loads the class with the specified <a href="#name">binary name</a>.
344 * This method searches for classes in the same manner as the {@link
345 * #loadClass(String, boolean)} method. It is invoked by the Java virtual
346 * machine to resolve class references. Invoking this method is equivalent
347 * to invoking {@link #loadClass(String, boolean) <tt>loadClass(name,
348 * false)</tt>}.
349 *
350 * @param name
351 * The <a href="#name">binary name</a> of the class
352 *
353 * @return The resulting <tt>Class</tt> object
354 *
355 * @throws ClassNotFoundException
356 * If the class was not found
357 */
358 public Class<?> loadClass(String name) throws ClassNotFoundException {
359 return loadClass(name, false);
360 }
361
362 /**
363 * Loads the class with the specified <a href="#name">binary name</a>. The
364 * default implementation of this method searches for classes in the
365 * following order:
366 *
367 * <ol>
368 *
369 * <li><p> Invoke {@link #findLoadedClass(String)} to check if the class
370 * has already been loaded. </p></li>
371 *
372 * <li><p> Invoke the {@link #loadClass(String) <tt>loadClass</tt>} method
373 * on the parent class loader. If the parent is <tt>null</tt> the class
374 * loader built-in to the virtual machine is used, instead. </p></li>
375 *
376 * <li><p> Invoke the {@link #findClass(String)} method to find the
377 * class. </p></li>
378 *
379 * </ol>
380 *
381 * <p> If the class was found using the above steps, and the
382 * <tt>resolve</tt> flag is true, this method will then invoke the {@link
383 * #resolveClass(Class)} method on the resulting <tt>Class</tt> object.
384 *
385 * <p> Subclasses of <tt>ClassLoader</tt> are encouraged to override {@link
386 * #findClass(String)}, rather than this method. </p>
387 *
388 * <p> Unless overridden, this method synchronizes on the result of
389 * {@link #getClassLoadingLock <tt>getClassLoadingLock</tt>} method
390 * during the entire class loading process.
391 *
392 * @param name
393 * The <a href="#name">binary name</a> of the class
394 *
395 * @param resolve
396 * If <tt>true</tt> then resolve the class
397 *
398 * @return The resulting <tt>Class</tt> object
399 *
400 * @throws ClassNotFoundException
401 * If the class could not be found
402 */
403 protected Class<?> loadClass(String name, boolean resolve)
404 throws ClassNotFoundException
405 {
406 synchronized (getClassLoadingLock(name)) {
407 // First, check if the class has already been loaded
408 Class<?> c = findLoadedClass(name);
409 if (c == null) {
410 long t0 = System.nanoTime();
411 try {
412 if (parent != null) {
413 c = parent.loadClass(name, false);
414 } else {
415 c = findBootstrapClassOrNull(name);
416 }
417 } catch (ClassNotFoundException e) {
418 // ClassNotFoundException thrown if class not found
419 // from the non-null parent class loader
420 }
421
422 if (c == null) {
423 // If still not found, then invoke findClass in order
424 // to find the class.
425 long t1 = System.nanoTime();
426 c = findClass(name);
427
428 // this is the defining class loader; record the stats
429 sun.misc.PerfCounter.getParentDelegationTime().addTime(t1 - t0);
430 sun.misc.PerfCounter.getFindClassTime().addElapsedTimeFrom(t1);
431 sun.misc.PerfCounter.getFindClasses().increment();
432 }
433 }
434 if (resolve) {
435 resolveClass(c);
436 }
437 return c;
438 }
439 }
440
441 /**
442 * Returns the lock object for class loading operations.
443 * For backward compatibility, the default implementation of this method
444 * behaves as follows. If this ClassLoader object is registered as
445 * parallel capable, the method returns a dedicated object associated
446 * with the specified class name. Otherwise, the method returns this
447 * ClassLoader object.
448 *
449 * @param className
450 * The name of the to-be-loaded class
451 *
452 * @return the lock for class loading operations
453 *
454 * @throws NullPointerException
455 * If registered as parallel capable and <tt>className</tt> is null
456 *
457 * @see #loadClass(String, boolean)
458 *
459 * @since 1.7
460 */
461 protected Object getClassLoadingLock(String className) {
462 Object lock = this;
463 if (parallelLockMap != null) {
464 Object newLock = new Object();
465 lock = parallelLockMap.putIfAbsent(className, newLock);
466 if (lock == null) {
467 lock = newLock;
468 }
469 }
470 return lock;
471 }
472
473 // This method is invoked by the virtual machine to load a class.
474 private Class<?> loadClassInternal(String name)
475 throws ClassNotFoundException
476 {
477 // For backward compatibility, explicitly lock on 'this' when
478 // the current class loader is not parallel capable.
479 if (parallelLockMap == null) {
480 synchronized (this) {
481 return loadClass(name);
482 }
483 } else {
484 return loadClass(name);
485 }
486 }
487
488 // Invoked by the VM after loading class with this loader.
489 private void checkPackageAccess(Class<?> cls, ProtectionDomain pd) {
490 final SecurityManager sm = System.getSecurityManager();
491 if (sm != null) {
492 if (ReflectUtil.isNonPublicProxyClass(cls)) {
493 for (Class<?> intf: cls.getInterfaces()) {
494 checkPackageAccess(intf, pd);
495 }
496 return;
497 }
498
499 final String name = cls.getName();
500 final int i = name.lastIndexOf('.');
501 if (i != -1) {
502 AccessController.doPrivileged(new PrivilegedAction<Void>() {
503 public Void run() {
504 sm.checkPackageAccess(name.substring(0, i));
505 return null;
506 }
507 }, new AccessControlContext(new ProtectionDomain[] {pd}));
508 }
509 }
510 domains.add(pd);
511 }
512
513 /**
514 * Finds the class with the specified <a href="#name">binary name</a>.
515 * This method should be overridden by class loader implementations that
516 * follow the delegation model for loading classes, and will be invoked by
517 * the {@link #loadClass <tt>loadClass</tt>} method after checking the
518 * parent class loader for the requested class. The default implementation
519 * throws a <tt>ClassNotFoundException</tt>.
520 *
521 * @param name
522 * The <a href="#name">binary name</a> of the class
523 *
524 * @return The resulting <tt>Class</tt> object
525 *
526 * @throws ClassNotFoundException
527 * If the class could not be found
528 *
529 * @since 1.2
530 */
531 protected Class<?> findClass(String name) throws ClassNotFoundException {
532 throw new ClassNotFoundException(name);
533 }
534
535 /**
536 * Converts an array of bytes into an instance of class <tt>Class</tt>.
537 * Before the <tt>Class</tt> can be used it must be resolved. This method
538 * is deprecated in favor of the version that takes a <a
539 * href="#name">binary name</a> as its first argument, and is more secure.
540 *
541 * @param b
542 * The bytes that make up the class data. The bytes in positions
543 * <tt>off</tt> through <tt>off+len-1</tt> should have the format
544 * of a valid class file as defined by
545 * <cite>The Java™ Virtual Machine Specification</cite>.
546 *
547 * @param off
548 * The start offset in <tt>b</tt> of the class data
549 *
550 * @param len
551 * The length of the class data
552 *
553 * @return The <tt>Class</tt> object that was created from the specified
554 * class data
555 *
556 * @throws ClassFormatError
557 * If the data did not contain a valid class
558 *
559 * @throws IndexOutOfBoundsException
560 * If either <tt>off</tt> or <tt>len</tt> is negative, or if
561 * <tt>off+len</tt> is greater than <tt>b.length</tt>.
562 *
563 * @throws SecurityException
564 * If an attempt is made to add this class to a package that
565 * contains classes that were signed by a different set of
566 * certificates than this class, or if an attempt is made
567 * to define a class in a package with a fully-qualified name
568 * that starts with "{@code java.}".
569 *
570 * @see #loadClass(String, boolean)
571 * @see #resolveClass(Class)
572 *
573 * @deprecated Replaced by {@link #defineClass(String, byte[], int, int)
574 * defineClass(String, byte[], int, int)}
575 */
576 @Deprecated
577 protected final Class<?> defineClass(byte[] b, int off, int len)
578 throws ClassFormatError
579 {
580 return defineClass(null, b, off, len, null);
581 }
582
583 /**
584 * Converts an array of bytes into an instance of class <tt>Class</tt>.
585 * Before the <tt>Class</tt> can be used it must be resolved.
586 *
587 * <p> This method assigns a default {@link java.security.ProtectionDomain
588 * <tt>ProtectionDomain</tt>} to the newly defined class. The
589 * <tt>ProtectionDomain</tt> is effectively granted the same set of
590 * permissions returned when {@link
591 * java.security.Policy#getPermissions(java.security.CodeSource)
592 * <tt>Policy.getPolicy().getPermissions(new CodeSource(null, null))</tt>}
593 * is invoked. The default domain is created on the first invocation of
594 * {@link #defineClass(String, byte[], int, int) <tt>defineClass</tt>},
595 * and re-used on subsequent invocations.
596 *
597 * <p> To assign a specific <tt>ProtectionDomain</tt> to the class, use
598 * the {@link #defineClass(String, byte[], int, int,
599 * java.security.ProtectionDomain) <tt>defineClass</tt>} method that takes a
600 * <tt>ProtectionDomain</tt> as one of its arguments. </p>
601 *
602 * @param name
603 * The expected <a href="#name">binary name</a> of the class, or
604 * <tt>null</tt> if not known
605 *
606 * @param b
607 * The bytes that make up the class data. The bytes in positions
608 * <tt>off</tt> through <tt>off+len-1</tt> should have the format
609 * of a valid class file as defined by
610 * <cite>The Java™ Virtual Machine Specification</cite>.
611 *
612 * @param off
613 * The start offset in <tt>b</tt> of the class data
614 *
615 * @param len
616 * The length of the class data
617 *
618 * @return The <tt>Class</tt> object that was created from the specified
619 * class data.
620 *
621 * @throws ClassFormatError
622 * If the data did not contain a valid class
623 *
624 * @throws IndexOutOfBoundsException
625 * If either <tt>off</tt> or <tt>len</tt> is negative, or if
626 * <tt>off+len</tt> is greater than <tt>b.length</tt>.
627 *
628 * @throws SecurityException
629 * If an attempt is made to add this class to a package that
630 * contains classes that were signed by a different set of
631 * certificates than this class (which is unsigned), or if
632 * <tt>name</tt> begins with "<tt>java.</tt>".
633 *
634 * @see #loadClass(String, boolean)
635 * @see #resolveClass(Class)
636 * @see java.security.CodeSource
637 * @see java.security.SecureClassLoader
638 *
639 * @since 1.1
640 */
641 protected final Class<?> defineClass(String name, byte[] b, int off, int len)
642 throws ClassFormatError
643 {
644 return defineClass(name, b, off, len, null);
645 }
646
647 /* Determine protection domain, and check that:
648 - not define java.* class,
649 - signer of this class matches signers for the rest of the classes in
650 package.
651 */
652 private ProtectionDomain preDefineClass(String name,
653 ProtectionDomain pd)
654 {
655 if (!checkName(name))
656 throw new NoClassDefFoundError("IllegalName: " + name);
657
658 if ((name != null) && name.startsWith("java.")) {
659 throw new SecurityException
660 ("Prohibited package name: " +
661 name.substring(0, name.lastIndexOf('.')));
662 }
663 if (pd == null) {
664 pd = defaultDomain;
665 }
666
667 if (name != null) checkCerts(name, pd.getCodeSource());
668
669 return pd;
670 }
671
672 private String defineClassSourceLocation(ProtectionDomain pd)
673 {
674 CodeSource cs = pd.getCodeSource();
675 String source = null;
676 if (cs != null && cs.getLocation() != null) {
677 source = cs.getLocation().toString();
678 }
679 return source;
680 }
681
682 private void postDefineClass(Class<?> c, ProtectionDomain pd)
683 {
684 if (pd.getCodeSource() != null) {
685 Certificate certs[] = pd.getCodeSource().getCertificates();
686 if (certs != null)
687 setSigners(c, certs);
688 }
689 }
690
691 /**
692 * Converts an array of bytes into an instance of class <tt>Class</tt>,
693 * with an optional <tt>ProtectionDomain</tt>. If the domain is
694 * <tt>null</tt>, then a default domain will be assigned to the class as
695 * specified in the documentation for {@link #defineClass(String, byte[],
696 * int, int)}. Before the class can be used it must be resolved.
697 *
698 * <p> The first class defined in a package determines the exact set of
699 * certificates that all subsequent classes defined in that package must
700 * contain. The set of certificates for a class is obtained from the
701 * {@link java.security.CodeSource <tt>CodeSource</tt>} within the
702 * <tt>ProtectionDomain</tt> of the class. Any classes added to that
703 * package must contain the same set of certificates or a
704 * <tt>SecurityException</tt> will be thrown. Note that if
705 * <tt>name</tt> is <tt>null</tt>, this check is not performed.
706 * You should always pass in the <a href="#name">binary name</a> of the
707 * class you are defining as well as the bytes. This ensures that the
708 * class you are defining is indeed the class you think it is.
709 *
710 * <p> The specified <tt>name</tt> cannot begin with "<tt>java.</tt>", since
711 * all classes in the "<tt>java.*</tt> packages can only be defined by the
712 * bootstrap class loader. If <tt>name</tt> is not <tt>null</tt>, it
713 * must be equal to the <a href="#name">binary name</a> of the class
714 * specified by the byte array "<tt>b</tt>", otherwise a {@link
715 * NoClassDefFoundError <tt>NoClassDefFoundError</tt>} will be thrown. </p>
716 *
717 * @param name
718 * The expected <a href="#name">binary name</a> of the class, or
719 * <tt>null</tt> if not known
720 *
721 * @param b
722 * The bytes that make up the class data. The bytes in positions
723 * <tt>off</tt> through <tt>off+len-1</tt> should have the format
724 * of a valid class file as defined by
725 * <cite>The Java™ Virtual Machine Specification</cite>.
726 *
727 * @param off
728 * The start offset in <tt>b</tt> of the class data
729 *
730 * @param len
731 * The length of the class data
732 *
733 * @param protectionDomain
734 * The ProtectionDomain of the class
735 *
736 * @return The <tt>Class</tt> object created from the data,
737 * and optional <tt>ProtectionDomain</tt>.
738 *
739 * @throws ClassFormatError
740 * If the data did not contain a valid class
741 *
742 * @throws NoClassDefFoundError
743 * If <tt>name</tt> is not equal to the <a href="#name">binary
744 * name</a> of the class specified by <tt>b</tt>
745 *
746 * @throws IndexOutOfBoundsException
747 * If either <tt>off</tt> or <tt>len</tt> is negative, or if
748 * <tt>off+len</tt> is greater than <tt>b.length</tt>.
749 *
750 * @throws SecurityException
751 * If an attempt is made to add this class to a package that
752 * contains classes that were signed by a different set of
753 * certificates than this class, or if <tt>name</tt> begins with
754 * "<tt>java.</tt>".
755 */
756 protected final Class<?> defineClass(String name, byte[] b, int off, int len,
757 ProtectionDomain protectionDomain)
758 throws ClassFormatError
759 {
760 protectionDomain = preDefineClass(name, protectionDomain);
761 String source = defineClassSourceLocation(protectionDomain);
762 Class<?> c = defineClass1(name, b, off, len, protectionDomain, source);
763 postDefineClass(c, protectionDomain);
764 return c;
765 }
766
767 /**
768 * Converts a {@link java.nio.ByteBuffer <tt>ByteBuffer</tt>}
769 * into an instance of class <tt>Class</tt>,
770 * with an optional <tt>ProtectionDomain</tt>. If the domain is
771 * <tt>null</tt>, then a default domain will be assigned to the class as
772 * specified in the documentation for {@link #defineClass(String, byte[],
773 * int, int)}. Before the class can be used it must be resolved.
774 *
775 * <p>The rules about the first class defined in a package determining the
776 * set of certificates for the package, and the restrictions on class names
777 * are identical to those specified in the documentation for {@link
778 * #defineClass(String, byte[], int, int, ProtectionDomain)}.
779 *
780 * <p> An invocation of this method of the form
781 * <i>cl</i><tt>.defineClass(</tt><i>name</i><tt>,</tt>
782 * <i>bBuffer</i><tt>,</tt> <i>pd</i><tt>)</tt> yields exactly the same
783 * result as the statements
784 *
785 *<p> <tt>
786 * ...<br>
787 * byte[] temp = new byte[bBuffer.{@link
788 * java.nio.ByteBuffer#remaining remaining}()];<br>
789 * bBuffer.{@link java.nio.ByteBuffer#get(byte[])
790 * get}(temp);<br>
791 * return {@link #defineClass(String, byte[], int, int, ProtectionDomain)
792 * cl.defineClass}(name, temp, 0,
793 * temp.length, pd);<br>
794 * </tt></p>
795 *
796 * @param name
797 * The expected <a href="#name">binary name</a>. of the class, or
798 * <tt>null</tt> if not known
799 *
800 * @param b
801 * The bytes that make up the class data. The bytes from positions
802 * <tt>b.position()</tt> through <tt>b.position() + b.limit() -1
803 * </tt> should have the format of a valid class file as defined by
804 * <cite>The Java™ Virtual Machine Specification</cite>.
805 *
806 * @param protectionDomain
807 * The ProtectionDomain of the class, or <tt>null</tt>.
808 *
809 * @return The <tt>Class</tt> object created from the data,
810 * and optional <tt>ProtectionDomain</tt>.
811 *
812 * @throws ClassFormatError
813 * If the data did not contain a valid class.
814 *
815 * @throws NoClassDefFoundError
816 * If <tt>name</tt> is not equal to the <a href="#name">binary
817 * name</a> of the class specified by <tt>b</tt>
818 *
819 * @throws SecurityException
820 * If an attempt is made to add this class to a package that
821 * contains classes that were signed by a different set of
822 * certificates than this class, or if <tt>name</tt> begins with
823 * "<tt>java.</tt>".
824 *
825 * @see #defineClass(String, byte[], int, int, ProtectionDomain)
826 *
827 * @since 1.5
828 */
829 protected final Class<?> defineClass(String name, java.nio.ByteBuffer b,
830 ProtectionDomain protectionDomain)
831 throws ClassFormatError
832 {
833 int len = b.remaining();
834
835 // Use byte[] if not a direct ByteBuffer:
836 if (!b.isDirect()) {
837 if (b.hasArray()) {
838 return defineClass(name, b.array(),
839 b.position() + b.arrayOffset(), len,
840 protectionDomain);
841 } else {
842 // no array, or read-only array
843 byte[] tb = new byte[len];
844 b.get(tb); // get bytes out of byte buffer.
845 return defineClass(name, tb, 0, len, protectionDomain);
846 }
847 }
848
849 protectionDomain = preDefineClass(name, protectionDomain);
850 String source = defineClassSourceLocation(protectionDomain);
851 Class<?> c = defineClass2(name, b, b.position(), len, protectionDomain, source);
852 postDefineClass(c, protectionDomain);
853 return c;
854 }
855
856 private native Class<?> defineClass1(String name, byte[] b, int off, int len,
857 ProtectionDomain pd, String source);
858
859 private native Class<?> defineClass2(String name, java.nio.ByteBuffer b,
860 int off, int len, ProtectionDomain pd,
861 String source);
862
863 // true if the name is null or has the potential to be a valid binary name
864 private boolean checkName(String name) {
865 if ((name == null) || (name.length() == 0))
866 return true;
867 if ((name.indexOf('/') != -1) || (name.charAt(0) == '['))
868 return false;
869 return true;
870 }
871
872 private void checkCerts(String name, CodeSource cs) {
873 int i = name.lastIndexOf('.');
874 String pname = (i == -1) ? "" : name.substring(0, i);
875
876 Certificate[] certs = null;
877 if (cs != null) {
878 certs = cs.getCertificates();
879 }
880 Certificate[] pcerts = null;
881 if (parallelLockMap == null) {
882 synchronized (this) {
883 pcerts = package2certs.get(pname);
884 if (pcerts == null) {
885 package2certs.put(pname, (certs == null? nocerts:certs));
886 }
887 }
888 } else {
889 pcerts = ((ConcurrentHashMap<String, Certificate[]>)package2certs).
890 putIfAbsent(pname, (certs == null? nocerts:certs));
891 }
892 if (pcerts != null && !compareCerts(pcerts, certs)) {
893 throw new SecurityException("class \""+ name +
894 "\"'s signer information does not match signer information of other classes in the same package");
895 }
896 }
897
898 /**
899 * check to make sure the certs for the new class (certs) are the same as
900 * the certs for the first class inserted in the package (pcerts)
901 */
902 private boolean compareCerts(Certificate[] pcerts,
903 Certificate[] certs)
904 {
905 // certs can be null, indicating no certs.
906 if ((certs == null) || (certs.length == 0)) {
907 return pcerts.length == 0;
908 }
909
910 // the length must be the same at this point
911 if (certs.length != pcerts.length)
912 return false;
913
914 // go through and make sure all the certs in one array
915 // are in the other and vice-versa.
916 boolean match;
917 for (Certificate cert : certs) {
918 match = false;
919 for (Certificate pcert : pcerts) {
920 if (cert.equals(pcert)) {
921 match = true;
922 break;
923 }
924 }
925 if (!match) return false;
926 }
927
928 // now do the same for pcerts
929 for (Certificate pcert : pcerts) {
930 match = false;
931 for (Certificate cert : certs) {
932 if (pcert.equals(cert)) {
933 match = true;
934 break;
935 }
936 }
937 if (!match) return false;
938 }
939
940 return true;
941 }
942
943 /**
944 * Links the specified class. This (misleadingly named) method may be
945 * used by a class loader to link a class. If the class <tt>c</tt> has
946 * already been linked, then this method simply returns. Otherwise, the
947 * class is linked as described in the "Execution" chapter of
948 * <cite>The Java™ Language Specification</cite>.
949 *
950 * @param c
951 * The class to link
952 *
953 * @throws NullPointerException
954 * If <tt>c</tt> is <tt>null</tt>.
955 *
956 * @see #defineClass(String, byte[], int, int)
957 */
958 protected final void resolveClass(Class<?> c) {
959 resolveClass0(c);
960 }
961
962 private native void resolveClass0(Class<?> c);
963
964 /**
965 * Finds a class with the specified <a href="#name">binary name</a>,
966 * loading it if necessary.
967 *
968 * <p> This method loads the class through the system class loader (see
969 * {@link #getSystemClassLoader()}). The <tt>Class</tt> object returned
970 * might have more than one <tt>ClassLoader</tt> associated with it.
971 * Subclasses of <tt>ClassLoader</tt> need not usually invoke this method,
972 * because most class loaders need to override just {@link
973 * #findClass(String)}. </p>
974 *
975 * @param name
976 * The <a href="#name">binary name</a> of the class
977 *
978 * @return The <tt>Class</tt> object for the specified <tt>name</tt>
979 *
980 * @throws ClassNotFoundException
981 * If the class could not be found
982 *
983 * @see #ClassLoader(ClassLoader)
984 * @see #getParent()
985 */
986 protected final Class<?> findSystemClass(String name)
987 throws ClassNotFoundException
988 {
989 ClassLoader system = getSystemClassLoader();
990 if (system == null) {
991 if (!checkName(name))
992 throw new ClassNotFoundException(name);
993 Class<?> cls = findBootstrapClass(name);
994 if (cls == null) {
995 throw new ClassNotFoundException(name);
996 }
997 return cls;
998 }
999 return system.loadClass(name);
1000 }
1001
1002 /**
1003 * Returns a class loaded by the bootstrap class loader;
1004 * or return null if not found.
1005 */
1006 private Class<?> findBootstrapClassOrNull(String name)
1007 {
1008 if (!checkName(name)) return null;
1009
1010 return findBootstrapClass(name);
1011 }
1012
1013 // return null if not found
1014 private native Class<?> findBootstrapClass(String name);
1015
1016 /**
1017 * Returns the class with the given <a href="#name">binary name</a> if this
1018 * loader has been recorded by the Java virtual machine as an initiating
1019 * loader of a class with that <a href="#name">binary name</a>. Otherwise
1020 * <tt>null</tt> is returned.
1021 *
1022 * @param name
1023 * The <a href="#name">binary name</a> of the class
1024 *
1025 * @return The <tt>Class</tt> object, or <tt>null</tt> if the class has
1026 * not been loaded
1027 *
1028 * @since 1.1
1029 */
1030 protected final Class<?> findLoadedClass(String name) {
1031 if (!checkName(name))
1032 return null;
1033 return findLoadedClass0(name);
1034 }
1035
1036 private native final Class<?> findLoadedClass0(String name);
1037
1038 /**
1039 * Sets the signers of a class. This should be invoked after defining a
1040 * class.
1041 *
1042 * @param c
1043 * The <tt>Class</tt> object
1044 *
1045 * @param signers
1046 * The signers for the class
1047 *
1048 * @since 1.1
1049 */
1050 protected final void setSigners(Class<?> c, Object[] signers) {
1051 c.setSigners(signers);
1052 }
1053
1054
1055 // -- Resource --
1056
1057 /**
1058 * Finds the resource with the given name. A resource is some data
1059 * (images, audio, text, etc) that can be accessed by class code in a way
1060 * that is independent of the location of the code.
1061 *
1062 * <p> The name of a resource is a '<tt>/</tt>'-separated path name that
1063 * identifies the resource.
1064 *
1065 * <p> This method will first search the parent class loader for the
1066 * resource; if the parent is <tt>null</tt> the path of the class loader
1067 * built-in to the virtual machine is searched. That failing, this method
1068 * will invoke {@link #findResource(String)} to find the resource. </p>
1069 *
1070 * @apiNote When overriding this method it is recommended that an
1071 * implementation ensures that any delegation is consistent with the {@link
1072 * #getResources(java.lang.String) getResources(String)} method.
1073 *
1074 * @param name
1075 * The resource name
1076 *
1077 * @return A <tt>URL</tt> object for reading the resource, or
1078 * <tt>null</tt> if the resource could not be found or the invoker
1079 * doesn't have adequate privileges to get the resource.
1080 *
1081 * @since 1.1
1082 */
1083 public URL getResource(String name) {
1084 URL url;
1085 if (parent != null) {
1086 url = parent.getResource(name);
1087 } else {
1088 url = getBootstrapResource(name);
1089 }
1090 if (url == null) {
1091 url = findResource(name);
1092 }
1093 return url;
1094 }
1095
1096 /**
1097 * Finds all the resources with the given name. A resource is some data
1098 * (images, audio, text, etc) that can be accessed by class code in a way
1099 * that is independent of the location of the code.
1100 *
1101 * <p>The name of a resource is a <tt>/</tt>-separated path name that
1102 * identifies the resource.
1103 *
1104 * <p> The search order is described in the documentation for {@link
1105 * #getResource(String)}. </p>
1106 *
1107 * @apiNote When overriding this method it is recommended that an
1108 * implementation ensures that any delegation is consistent with the {@link
1109 * #getResource(java.lang.String) getResource(String)} method. This should
1110 * ensure that the first element returned by the Enumeration's
1111 * {@code nextElement} method is the same resource that the
1112 * {@code getResource(String)} method would return.
1113 *
1114 * @param name
1115 * The resource name
1116 *
1117 * @return An enumeration of {@link java.net.URL <tt>URL</tt>} objects for
1118 * the resource. If no resources could be found, the enumeration
1119 * will be empty. Resources that the class loader doesn't have
1120 * access to will not be in the enumeration.
1121 *
1122 * @throws IOException
1123 * If I/O errors occur
1124 *
1125 * @see #findResources(String)
1126 *
1127 * @since 1.2
1128 */
1129 public Enumeration<URL> getResources(String name) throws IOException {
1130 @SuppressWarnings("unchecked")
1131 Enumeration<URL>[] tmp = (Enumeration<URL>[]) new Enumeration<?>[2];
1132 if (parent != null) {
1133 tmp[0] = parent.getResources(name);
1134 } else {
1135 tmp[0] = getBootstrapResources(name);
1136 }
1137 tmp[1] = findResources(name);
1138
1139 return new CompoundEnumeration<>(tmp);
1140 }
1141
1142 /**
1143 * Finds the resource with the given name. Class loader implementations
1144 * should override this method to specify where to find resources.
1145 *
1146 * @param name
1147 * The resource name
1148 *
1149 * @return A <tt>URL</tt> object for reading the resource, or
1150 * <tt>null</tt> if the resource could not be found
1151 *
1152 * @since 1.2
1153 */
1154 protected URL findResource(String name) {
1155 return null;
1156 }
1157
1158 /**
1159 * Returns an enumeration of {@link java.net.URL <tt>URL</tt>} objects
1160 * representing all the resources with the given name. Class loader
1161 * implementations should override this method to specify where to load
1162 * resources from.
1163 *
1164 * @param name
1165 * The resource name
1166 *
1167 * @return An enumeration of {@link java.net.URL <tt>URL</tt>} objects for
1168 * the resources
1169 *
1170 * @throws IOException
1171 * If I/O errors occur
1172 *
1173 * @since 1.2
1174 */
1175 protected Enumeration<URL> findResources(String name) throws IOException {
1176 return java.util.Collections.emptyEnumeration();
1177 }
1178
1179 /**
1180 * Registers the caller as parallel capable.
1181 * The registration succeeds if and only if all of the following
1182 * conditions are met:
1183 * <ol>
1184 * <li> no instance of the caller has been created</li>
1185 * <li> all of the super classes (except class Object) of the caller are
1186 * registered as parallel capable</li>
1187 * </ol>
1188 * <p>Note that once a class loader is registered as parallel capable, there
1189 * is no way to change it back.</p>
1190 *
1191 * @return true if the caller is successfully registered as
1192 * parallel capable and false if otherwise.
1193 *
1194 * @since 1.7
1195 */
1196 @CallerSensitive
1197 protected static boolean registerAsParallelCapable() {
1198 Class<? extends ClassLoader> callerClass =
1199 Reflection.getCallerClass().asSubclass(ClassLoader.class);
1200 return ParallelLoaders.register(callerClass);
1201 }
1202
1203 /**
1204 * Find a resource of the specified name from the search path used to load
1205 * classes. This method locates the resource through the system class
1206 * loader (see {@link #getSystemClassLoader()}).
1207 *
1208 * @param name
1209 * The resource name
1210 *
1211 * @return A {@link java.net.URL <tt>URL</tt>} object for reading the
1212 * resource, or <tt>null</tt> if the resource could not be found
1213 *
1214 * @since 1.1
1215 */
1216 public static URL getSystemResource(String name) {
1217 ClassLoader system = getSystemClassLoader();
1218 if (system == null) {
1219 return getBootstrapResource(name);
1220 }
1221 return system.getResource(name);
1222 }
1223
1224 /**
1225 * Finds all resources of the specified name from the search path used to
1226 * load classes. The resources thus found are returned as an
1227 * {@link java.util.Enumeration <tt>Enumeration</tt>} of {@link
1228 * java.net.URL <tt>URL</tt>} objects.
1229 *
1230 * <p> The search order is described in the documentation for {@link
1231 * #getSystemResource(String)}. </p>
1232 *
1233 * @param name
1234 * The resource name
1235 *
1236 * @return An enumeration of resource {@link java.net.URL <tt>URL</tt>}
1237 * objects
1238 *
1239 * @throws IOException
1240 * If I/O errors occur
1241
1242 * @since 1.2
1243 */
1244 public static Enumeration<URL> getSystemResources(String name)
1245 throws IOException
1246 {
1247 ClassLoader system = getSystemClassLoader();
1248 if (system == null) {
1249 return getBootstrapResources(name);
1250 }
1251 return system.getResources(name);
1252 }
1253
1254 /**
1255 * Find resources from the VM's built-in classloader.
1256 */
1257 private static URL getBootstrapResource(String name) {
1258 URLClassPath ucp = getBootstrapClassPath();
1259 Resource res = ucp.getResource(name);
1260 return res != null ? res.getURL() : null;
1261 }
1262
1263 /**
1264 * Find resources from the VM's built-in classloader.
1265 */
1266 private static Enumeration<URL> getBootstrapResources(String name)
1267 throws IOException
1268 {
1269 final Enumeration<Resource> e =
1270 getBootstrapClassPath().getResources(name);
1271 return new Enumeration<URL> () {
1272 public URL nextElement() {
1273 return e.nextElement().getURL();
1274 }
1275 public boolean hasMoreElements() {
1276 return e.hasMoreElements();
1277 }
1278 };
1279 }
1280
1281 // Returns the URLClassPath that is used for finding system resources.
1282 static URLClassPath getBootstrapClassPath() {
1283 return sun.misc.Launcher.getBootstrapClassPath();
1284 }
1285
1286
1287 /**
1288 * Returns an input stream for reading the specified resource.
1289 *
1290 * <p> The search order is described in the documentation for {@link
1291 * #getResource(String)}. </p>
1292 *
1293 * @param name
1294 * The resource name
1295 *
1296 * @return An input stream for reading the resource, or <tt>null</tt>
1297 * if the resource could not be found
1298 *
1299 * @since 1.1
1300 */
1301 public InputStream getResourceAsStream(String name) {
1302 URL url = getResource(name);
1303 try {
1304 return url != null ? url.openStream() : null;
1305 } catch (IOException e) {
1306 return null;
1307 }
1308 }
1309
1310 /**
1311 * Open for reading, a resource of the specified name from the search path
1312 * used to load classes. This method locates the resource through the
1313 * system class loader (see {@link #getSystemClassLoader()}).
1314 *
1315 * @param name
1316 * The resource name
1317 *
1318 * @return An input stream for reading the resource, or <tt>null</tt>
1319 * if the resource could not be found
1320 *
1321 * @since 1.1
1322 */
1323 public static InputStream getSystemResourceAsStream(String name) {
1324 URL url = getSystemResource(name);
1325 try {
1326 return url != null ? url.openStream() : null;
1327 } catch (IOException e) {
1328 return null;
1329 }
1330 }
1331
1332
1333 // -- Hierarchy --
1334
1335 /**
1336 * Returns the parent class loader for delegation. Some implementations may
1337 * use <tt>null</tt> to represent the bootstrap class loader. This method
1338 * will return <tt>null</tt> in such implementations if this class loader's
1339 * parent is the bootstrap class loader.
1340 *
1341 * <p> If a security manager is present, and the invoker's class loader is
1342 * not <tt>null</tt> and is not an ancestor of this class loader, then this
1343 * method invokes the security manager's {@link
1344 * SecurityManager#checkPermission(java.security.Permission)
1345 * <tt>checkPermission</tt>} method with a {@link
1346 * RuntimePermission#RuntimePermission(String)
1347 * <tt>RuntimePermission("getClassLoader")</tt>} permission to verify
1348 * access to the parent class loader is permitted. If not, a
1349 * <tt>SecurityException</tt> will be thrown. </p>
1350 *
1351 * @return The parent <tt>ClassLoader</tt>
1352 *
1353 * @throws SecurityException
1354 * If a security manager exists and its <tt>checkPermission</tt>
1355 * method doesn't allow access to this class loader's parent class
1356 * loader.
1357 *
1358 * @since 1.2
1359 */
1360 @CallerSensitive
1361 public final ClassLoader getParent() {
1362 if (parent == null)
1363 return null;
1364 SecurityManager sm = System.getSecurityManager();
1365 if (sm != null) {
1366 checkClassLoaderPermission(this, Reflection.getCallerClass());
1367 }
1368 return parent;
1369 }
1370
1371 /**
1372 * Returns the system class loader for delegation. This is the default
1373 * delegation parent for new <tt>ClassLoader</tt> instances, and is
1374 * typically the class loader used to start the application.
1375 *
1376 * <p> This method is first invoked early in the runtime's startup
1377 * sequence, at which point it creates the system class loader and sets it
1378 * as the context class loader of the invoking <tt>Thread</tt>.
1379 *
1380 * <p> The default system class loader is an implementation-dependent
1381 * instance of this class.
1382 *
1383 * <p> If the system property "<tt>java.system.class.loader</tt>" is defined
1384 * when this method is first invoked then the value of that property is
1385 * taken to be the name of a class that will be returned as the system
1386 * class loader. The class is loaded using the default system class loader
1387 * and must define a public constructor that takes a single parameter of
1388 * type <tt>ClassLoader</tt> which is used as the delegation parent. An
1389 * instance is then created using this constructor with the default system
1390 * class loader as the parameter. The resulting class loader is defined
1391 * to be the system class loader.
1392 *
1393 * <p> If a security manager is present, and the invoker's class loader is
1394 * not <tt>null</tt> and the invoker's class loader is not the same as or
1395 * an ancestor of the system class loader, then this method invokes the
1396 * security manager's {@link
1397 * SecurityManager#checkPermission(java.security.Permission)
1398 * <tt>checkPermission</tt>} method with a {@link
1399 * RuntimePermission#RuntimePermission(String)
1400 * <tt>RuntimePermission("getClassLoader")</tt>} permission to verify
1401 * access to the system class loader. If not, a
1402 * <tt>SecurityException</tt> will be thrown. </p>
1403 *
1404 * @return The system <tt>ClassLoader</tt> for delegation, or
1405 * <tt>null</tt> if none
1406 *
1407 * @throws SecurityException
1408 * If a security manager exists and its <tt>checkPermission</tt>
1409 * method doesn't allow access to the system class loader.
1410 *
1411 * @throws IllegalStateException
1412 * If invoked recursively during the construction of the class
1413 * loader specified by the "<tt>java.system.class.loader</tt>"
1414 * property.
1415 *
1416 * @throws Error
1417 * If the system property "<tt>java.system.class.loader</tt>"
1418 * is defined but the named class could not be loaded, the
1419 * provider class does not define the required constructor, or an
1420 * exception is thrown by that constructor when it is invoked. The
1421 * underlying cause of the error can be retrieved via the
1422 * {@link Throwable#getCause()} method.
1423 *
1424 * @revised 1.4
1425 */
1426 @CallerSensitive
1427 public static ClassLoader getSystemClassLoader() {
1428 initSystemClassLoader();
1429 if (scl == null) {
1430 return null;
1431 }
1432 SecurityManager sm = System.getSecurityManager();
1433 if (sm != null) {
1434 checkClassLoaderPermission(scl, Reflection.getCallerClass());
1435 }
1436 return scl;
1437 }
1438
1439 private static synchronized void initSystemClassLoader() {
1440 if (!sclSet) {
1441 if (scl != null)
1442 throw new IllegalStateException("recursive invocation");
1443 sun.misc.Launcher l = sun.misc.Launcher.getLauncher();
1444 if (l != null) {
1445 Throwable oops = null;
1446 scl = l.getClassLoader();
1447 try {
1448 scl = AccessController.doPrivileged(
1449 new SystemClassLoaderAction(scl));
1450 } catch (PrivilegedActionException pae) {
1451 oops = pae.getCause();
1452 if (oops instanceof InvocationTargetException) {
1453 oops = oops.getCause();
1454 }
1455 }
1456 if (oops != null) {
1457 if (oops instanceof Error) {
1458 throw (Error) oops;
1459 } else {
1460 // wrap the exception
1461 throw new Error(oops);
1462 }
1463 }
1464 }
1465 sclSet = true;
1466 }
1467 }
1468
1469 // Returns true if the specified class loader can be found in this class
1470 // loader's delegation chain.
1471 boolean isAncestor(ClassLoader cl) {
1472 ClassLoader acl = this;
1473 do {
1474 acl = acl.parent;
1475 if (cl == acl) {
1476 return true;
1477 }
1478 } while (acl != null);
1479 return false;
1480 }
1481
1482 // Tests if class loader access requires "getClassLoader" permission
1483 // check. A class loader 'from' can access class loader 'to' if
1484 // class loader 'from' is same as class loader 'to' or an ancestor
1485 // of 'to'. The class loader in a system domain can access
1486 // any class loader.
1487 private static boolean needsClassLoaderPermissionCheck(ClassLoader from,
1488 ClassLoader to)
1489 {
1490 if (from == to)
1491 return false;
1492
1493 if (from == null)
1494 return false;
1495
1496 return !to.isAncestor(from);
1497 }
1498
1499 // Returns the class's class loader, or null if none.
1500 static ClassLoader getClassLoader(Class<?> caller) {
1501 // This can be null if the VM is requesting it
1502 if (caller == null) {
1503 return null;
1504 }
1505 // Circumvent security check since this is package-private
1506 return caller.getClassLoader0();
1507 }
1508
1509 static void checkClassLoaderPermission(ClassLoader cl, Class<?> caller) {
1510 SecurityManager sm = System.getSecurityManager();
1511 if (sm != null) {
1512 // caller can be null if the VM is requesting it
1513 ClassLoader ccl = getClassLoader(caller);
1514 if (needsClassLoaderPermissionCheck(ccl, cl)) {
1515 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
1516 }
1517 }
1518 }
1519
1520 // The class loader for the system
1521 // @GuardedBy("ClassLoader.class")
1522 private static ClassLoader scl;
1523
1524 // Set to true once the system class loader has been set
1525 // @GuardedBy("ClassLoader.class")
1526 private static boolean sclSet;
1527
1528
1529 // -- Package --
1530
1531 /**
1532 * Defines a package by name in this <tt>ClassLoader</tt>. This allows
1533 * class loaders to define the packages for their classes. Packages must
1534 * be created before the class is defined, and package names must be
1535 * unique within a class loader and cannot be redefined or changed once
1536 * created.
1537 *
1538 * @param name
1539 * The package name
1540 *
1541 * @param specTitle
1542 * The specification title
1543 *
1544 * @param specVersion
1545 * The specification version
1546 *
1547 * @param specVendor
1548 * The specification vendor
1549 *
1550 * @param implTitle
1551 * The implementation title
1552 *
1553 * @param implVersion
1554 * The implementation version
1555 *
1556 * @param implVendor
1557 * The implementation vendor
1558 *
1559 * @param sealBase
1560 * If not <tt>null</tt>, then this package is sealed with
1561 * respect to the given code source {@link java.net.URL
1562 * <tt>URL</tt>} object. Otherwise, the package is not sealed.
1563 *
1564 * @return The newly defined <tt>Package</tt> object
1565 *
1566 * @throws IllegalArgumentException
1567 * If package name duplicates an existing package either in this
1568 * class loader or one of its ancestors
1569 *
1570 * @since 1.2
1571 */
1572 protected Package definePackage(String name, String specTitle,
1573 String specVersion, String specVendor,
1574 String implTitle, String implVersion,
1575 String implVendor, URL sealBase)
1576 throws IllegalArgumentException
1577 {
1578 synchronized (packages) {
1579 Package pkg = getPackage(name);
1580 if (pkg != null) {
1581 throw new IllegalArgumentException(name);
1582 }
1583 pkg = new Package(name, specTitle, specVersion, specVendor,
1584 implTitle, implVersion, implVendor,
1585 sealBase, this);
1586 packages.put(name, pkg);
1587 return pkg;
1588 }
1589 }
1590
1591 /**
1592 * Returns a <tt>Package</tt> that has been defined by this class loader
1593 * or any of its ancestors.
1594 *
1595 * @param name
1596 * The package name
1597 *
1598 * @return The <tt>Package</tt> corresponding to the given name, or
1599 * <tt>null</tt> if not found
1600 *
1601 * @since 1.2
1602 */
1603 protected Package getPackage(String name) {
1604 Package pkg;
1605 synchronized (packages) {
1606 pkg = packages.get(name);
1607 }
1608 if (pkg == null) {
1609 if (parent != null) {
1610 pkg = parent.getPackage(name);
1611 } else {
1612 pkg = Package.getSystemPackage(name);
1613 }
1614 if (pkg != null) {
1615 synchronized (packages) {
1616 Package pkg2 = packages.get(name);
1617 if (pkg2 == null) {
1618 packages.put(name, pkg);
1619 } else {
1620 pkg = pkg2;
1621 }
1622 }
1623 }
1624 }
1625 return pkg;
1626 }
1627
1628 /**
1629 * Returns all of the <tt>Packages</tt> defined by this class loader and
1630 * its ancestors.
1631 *
1632 * @return The array of <tt>Package</tt> objects defined by this
1633 * <tt>ClassLoader</tt>
1634 *
1635 * @since 1.2
1636 */
1637 protected Package[] getPackages() {
1638 Map<String, Package> map;
1639 synchronized (packages) {
1640 map = new HashMap<>(packages);
1641 }
1642 Package[] pkgs;
1643 if (parent != null) {
1644 pkgs = parent.getPackages();
1645 } else {
1646 pkgs = Package.getSystemPackages();
1647 }
1648 if (pkgs != null) {
1649 for (Package pkg : pkgs) {
1650 String pkgName = pkg.getName();
1651 if (map.get(pkgName) == null) {
1652 map.put(pkgName, pkg);
1653 }
1654 }
1655 }
1656 return map.values().toArray(new Package[map.size()]);
1657 }
1658
1659
1660 // -- Native library access --
1661
1662 /**
1663 * Returns the absolute path name of a native library. The VM invokes this
1664 * method to locate the native libraries that belong to classes loaded with
1665 * this class loader. If this method returns <tt>null</tt>, the VM
1666 * searches the library along the path specified as the
1667 * "<tt>java.library.path</tt>" property.
1668 *
1669 * @param libname
1670 * The library name
1671 *
1672 * @return The absolute path of the native library
1673 *
1674 * @see System#loadLibrary(String)
1675 * @see System#mapLibraryName(String)
1676 *
1677 * @since 1.2
1678 */
1679 protected String findLibrary(String libname) {
1680 return null;
1681 }
1682
1683 /**
1684 * The inner class NativeLibrary denotes a loaded native library instance.
1685 * Every classloader contains a vector of loaded native libraries in the
1686 * private field <tt>nativeLibraries</tt>. The native libraries loaded
1687 * into the system are entered into the <tt>systemNativeLibraries</tt>
1688 * vector.
1689 *
1690 * <p> Every native library requires a particular version of JNI. This is
1691 * denoted by the private <tt>jniVersion</tt> field. This field is set by
1692 * the VM when it loads the library, and used by the VM to pass the correct
1693 * version of JNI to the native methods. </p>
1694 *
1695 * @see ClassLoader
1696 * @since 1.2
1697 */
1698 static class NativeLibrary {
1699 // opaque handle to native library, used in native code.
1700 long handle;
1701 // the version of JNI environment the native library requires.
1702 private int jniVersion;
1703 // the class from which the library is loaded, also indicates
1704 // the loader this native library belongs.
1705 private final Class<?> fromClass;
1706 // the canonicalized name of the native library.
1707 // or static library name
1708 String name;
1709 // Indicates if the native library is linked into the VM
1710 boolean isBuiltin;
1711 // Indicates if the native library is loaded
1712 boolean loaded;
1713 native void load(String name, boolean isBuiltin);
1714
1715 native long find(String name);
1716 native void unload(String name, boolean isBuiltin);
1717 static native String findBuiltinLib(String name);
1718
1719 public NativeLibrary(Class<?> fromClass, String name, boolean isBuiltin) {
1720 this.name = name;
1721 this.fromClass = fromClass;
1722 this.isBuiltin = isBuiltin;
1723 }
1724
1725 protected void finalize() {
1726 synchronized (loadedLibraryNames) {
1727 if (fromClass.getClassLoader() != null && loaded) {
1728 /* remove the native library name */
1729 int size = loadedLibraryNames.size();
1730 for (int i = 0; i < size; i++) {
1731 if (name.equals(loadedLibraryNames.elementAt(i))) {
1732 loadedLibraryNames.removeElementAt(i);
1733 break;
1734 }
1735 }
1736 /* unload the library. */
1737 ClassLoader.nativeLibraryContext.push(this);
1738 try {
1739 unload(name, isBuiltin);
1740 } finally {
1741 ClassLoader.nativeLibraryContext.pop();
1742 }
1743 }
1744 }
1745 }
1746 // Invoked in the VM to determine the context class in
1747 // JNI_Load/JNI_Unload
1748 static Class<?> getFromClass() {
1749 return ClassLoader.nativeLibraryContext.peek().fromClass;
1750 }
1751 }
1752
1753 // All native library names we've loaded.
1754 private static Vector<String> loadedLibraryNames = new Vector<>();
1755
1756 // Native libraries belonging to system classes.
1757 private static Vector<NativeLibrary> systemNativeLibraries
1758 = new Vector<>();
1759
1760 // Native libraries associated with the class loader.
1761 private Vector<NativeLibrary> nativeLibraries = new Vector<>();
1762
1763 // native libraries being loaded/unloaded.
1764 private static Stack<NativeLibrary> nativeLibraryContext = new Stack<>();
1765
1766 // The paths searched for libraries
1767 private static String usr_paths[];
1768 private static String sys_paths[];
1769
1770 private static String[] initializePath(String propname) {
1771 String ldpath = System.getProperty(propname, "");
1772 String ps = File.pathSeparator;
1773 int ldlen = ldpath.length();
1774 int i, j, n;
1775 // Count the separators in the path
1776 i = ldpath.indexOf(ps);
1777 n = 0;
1778 while (i >= 0) {
1779 n++;
1780 i = ldpath.indexOf(ps, i + 1);
1781 }
1782
1783 // allocate the array of paths - n :'s = n + 1 path elements
1784 String[] paths = new String[n + 1];
1785
1786 // Fill the array with paths from the ldpath
1787 n = i = 0;
1788 j = ldpath.indexOf(ps);
1789 while (j >= 0) {
1790 if (j - i > 0) {
1791 paths[n++] = ldpath.substring(i, j);
1792 } else if (j - i == 0) {
1793 paths[n++] = ".";
1794 }
1795 i = j + 1;
1796 j = ldpath.indexOf(ps, i);
1797 }
1798 paths[n] = ldpath.substring(i, ldlen);
1799 return paths;
1800 }
1801
1802 // Invoked in the java.lang.Runtime class to implement load and loadLibrary.
1803 static void loadLibrary(Class<?> fromClass, String name,
1804 boolean isAbsolute) {
1805 ClassLoader loader =
1806 (fromClass == null) ? null : fromClass.getClassLoader();
1807 if (sys_paths == null) {
1808 usr_paths = initializePath("java.library.path");
1809 sys_paths = initializePath("sun.boot.library.path");
1810 }
1811 if (isAbsolute) {
1812 if (loadLibrary0(fromClass, new File(name))) {
1813 return;
1814 }
1815 throw new UnsatisfiedLinkError("Can't load library: " + name);
1816 }
1817 if (loader != null) {
1818 String libfilename = loader.findLibrary(name);
1819 if (libfilename != null) {
1820 File libfile = new File(libfilename);
1821 if (!libfile.isAbsolute()) {
1822 throw new UnsatisfiedLinkError(
1823 "ClassLoader.findLibrary failed to return an absolute path: " + libfilename);
1824 }
1825 if (loadLibrary0(fromClass, libfile)) {
1826 return;
1827 }
1828 throw new UnsatisfiedLinkError("Can't load " + libfilename);
1829 }
1830 }
1831 for (String sys_path : sys_paths) {
1832 File libfile = new File(sys_path, System.mapLibraryName(name));
1833 if (loadLibrary0(fromClass, libfile)) {
1834 return;
1835 }
1836 libfile = ClassLoaderHelper.mapAlternativeName(libfile);
1837 if (libfile != null && loadLibrary0(fromClass, libfile)) {
1838 return;
1839 }
1840 }
1841 if (loader != null) {
1842 for (String usr_path : usr_paths) {
1843 File libfile = new File(usr_path, System.mapLibraryName(name));
1844 if (loadLibrary0(fromClass, libfile)) {
1845 return;
1846 }
1847 libfile = ClassLoaderHelper.mapAlternativeName(libfile);
1848 if (libfile != null && loadLibrary0(fromClass, libfile)) {
1849 return;
1850 }
1851 }
1852 }
1853 // Oops, it failed
1854 throw new UnsatisfiedLinkError("no " + name + " in java.library.path");
1855 }
1856
1857 private static boolean loadLibrary0(Class<?> fromClass, final File file) {
1858 // Check to see if we're attempting to access a static library
1859 String name = NativeLibrary.findBuiltinLib(file.getName());
1860 boolean isBuiltin = (name != null);
1861 if (!isBuiltin) {
1862 name = AccessController.doPrivileged(
1863 new PrivilegedAction<String>() {
1864 public String run() {
1865 try {
1866 return file.exists() ? file.getCanonicalPath() : null;
1867 } catch (IOException e) {
1868 return null;
1869 }
1870 }
1871 });
1872 if (name == null) {
1873 return false;
1874 }
1875 }
1876 ClassLoader loader =
1877 (fromClass == null) ? null : fromClass.getClassLoader();
1878 Vector<NativeLibrary> libs =
1879 loader != null ? loader.nativeLibraries : systemNativeLibraries;
1880 synchronized (libs) {
1881 int size = libs.size();
1882 for (int i = 0; i < size; i++) {
1883 NativeLibrary lib = libs.elementAt(i);
1884 if (name.equals(lib.name)) {
1885 return true;
1886 }
1887 }
1888
1889 synchronized (loadedLibraryNames) {
1890 if (loadedLibraryNames.contains(name)) {
1891 throw new UnsatisfiedLinkError
1892 ("Native Library " +
1893 name +
1894 " already loaded in another classloader");
1895 }
1896 /* If the library is being loaded (must be by the same thread,
1897 * because Runtime.load and Runtime.loadLibrary are
1898 * synchronous). The reason is can occur is that the JNI_OnLoad
1899 * function can cause another loadLibrary invocation.
1900 *
1901 * Thus we can use a static stack to hold the list of libraries
1902 * we are loading.
1903 *
1904 * If there is a pending load operation for the library, we
1905 * immediately return success; otherwise, we raise
1906 * UnsatisfiedLinkError.
1907 */
1908 int n = nativeLibraryContext.size();
1909 for (int i = 0; i < n; i++) {
1910 NativeLibrary lib = nativeLibraryContext.elementAt(i);
1911 if (name.equals(lib.name)) {
1912 if (loader == lib.fromClass.getClassLoader()) {
1913 return true;
1914 } else {
1915 throw new UnsatisfiedLinkError
1916 ("Native Library " +
1917 name +
1918 " is being loaded in another classloader");
1919 }
1920 }
1921 }
1922 NativeLibrary lib = new NativeLibrary(fromClass, name, isBuiltin);
1923 nativeLibraryContext.push(lib);
1924 try {
1925 lib.load(name, isBuiltin);
1926 } finally {
1927 nativeLibraryContext.pop();
1928 }
1929 if (lib.loaded) {
1930 loadedLibraryNames.addElement(name);
1931 libs.addElement(lib);
1932 return true;
1933 }
1934 return false;
1935 }
1936 }
1937 }
1938
1939 // Invoked in the VM class linking code.
1940 static long findNative(ClassLoader loader, String name) {
1941 Vector<NativeLibrary> libs =
1942 loader != null ? loader.nativeLibraries : systemNativeLibraries;
1943 synchronized (libs) {
1944 int size = libs.size();
1945 for (int i = 0; i < size; i++) {
1946 NativeLibrary lib = libs.elementAt(i);
1947 long entry = lib.find(name);
1948 if (entry != 0)
1949 return entry;
1950 }
1951 }
1952 return 0;
1953 }
1954
1955
1956 // -- Assertion management --
1957
1958 final Object assertionLock;
1959
1960 // The default toggle for assertion checking.
1961 // @GuardedBy("assertionLock")
1962 private boolean defaultAssertionStatus = false;
1963
1964 // Maps String packageName to Boolean package default assertion status Note
1965 // that the default package is placed under a null map key. If this field
1966 // is null then we are delegating assertion status queries to the VM, i.e.,
1967 // none of this ClassLoader's assertion status modification methods have
1968 // been invoked.
1969 // @GuardedBy("assertionLock")
1970 private Map<String, Boolean> packageAssertionStatus = null;
1971
1972 // Maps String fullyQualifiedClassName to Boolean assertionStatus If this
1973 // field is null then we are delegating assertion status queries to the VM,
1974 // i.e., none of this ClassLoader's assertion status modification methods
1975 // have been invoked.
1976 // @GuardedBy("assertionLock")
1977 Map<String, Boolean> classAssertionStatus = null;
1978
1979 /**
1980 * Sets the default assertion status for this class loader. This setting
1981 * determines whether classes loaded by this class loader and initialized
1982 * in the future will have assertions enabled or disabled by default.
1983 * This setting may be overridden on a per-package or per-class basis by
1984 * invoking {@link #setPackageAssertionStatus(String, boolean)} or {@link
1985 * #setClassAssertionStatus(String, boolean)}.
1986 *
1987 * @param enabled
1988 * <tt>true</tt> if classes loaded by this class loader will
1989 * henceforth have assertions enabled by default, <tt>false</tt>
1990 * if they will have assertions disabled by default.
1991 *
1992 * @since 1.4
1993 */
1994 public void setDefaultAssertionStatus(boolean enabled) {
1995 synchronized (assertionLock) {
1996 if (classAssertionStatus == null)
1997 initializeJavaAssertionMaps();
1998
1999 defaultAssertionStatus = enabled;
2000 }
2001 }
2002
2003 /**
2004 * Sets the package default assertion status for the named package. The
2005 * package default assertion status determines the assertion status for
2006 * classes initialized in the future that belong to the named package or
2007 * any of its "subpackages".
2008 *
2009 * <p> A subpackage of a package named p is any package whose name begins
2010 * with "<tt>p.</tt>". For example, <tt>javax.swing.text</tt> is a
2011 * subpackage of <tt>javax.swing</tt>, and both <tt>java.util</tt> and
2012 * <tt>java.lang.reflect</tt> are subpackages of <tt>java</tt>.
2013 *
2014 * <p> In the event that multiple package defaults apply to a given class,
2015 * the package default pertaining to the most specific package takes
2016 * precedence over the others. For example, if <tt>javax.lang</tt> and
2017 * <tt>javax.lang.reflect</tt> both have package defaults associated with
2018 * them, the latter package default applies to classes in
2019 * <tt>javax.lang.reflect</tt>.
2020 *
2021 * <p> Package defaults take precedence over the class loader's default
2022 * assertion status, and may be overridden on a per-class basis by invoking
2023 * {@link #setClassAssertionStatus(String, boolean)}. </p>
2024 *
2025 * @param packageName
2026 * The name of the package whose package default assertion status
2027 * is to be set. A <tt>null</tt> value indicates the unnamed
2028 * package that is "current"
2029 * (see section 7.4.2 of
2030 * <cite>The Java™ Language Specification</cite>.)
2031 *
2032 * @param enabled
2033 * <tt>true</tt> if classes loaded by this classloader and
2034 * belonging to the named package or any of its subpackages will
2035 * have assertions enabled by default, <tt>false</tt> if they will
2036 * have assertions disabled by default.
2037 *
2038 * @since 1.4
2039 */
2040 public void setPackageAssertionStatus(String packageName,
2041 boolean enabled) {
2042 synchronized (assertionLock) {
2043 if (packageAssertionStatus == null)
2044 initializeJavaAssertionMaps();
2045
2046 packageAssertionStatus.put(packageName, enabled);
2047 }
2048 }
2049
2050 /**
2051 * Sets the desired assertion status for the named top-level class in this
2052 * class loader and any nested classes contained therein. This setting
2053 * takes precedence over the class loader's default assertion status, and
2054 * over any applicable per-package default. This method has no effect if
2055 * the named class has already been initialized. (Once a class is
2056 * initialized, its assertion status cannot change.)
2057 *
2058 * <p> If the named class is not a top-level class, this invocation will
2059 * have no effect on the actual assertion status of any class. </p>
2060 *
2061 * @param className
2062 * The fully qualified class name of the top-level class whose
2063 * assertion status is to be set.
2064 *
2065 * @param enabled
2066 * <tt>true</tt> if the named class is to have assertions
2067 * enabled when (and if) it is initialized, <tt>false</tt> if the
2068 * class is to have assertions disabled.
2069 *
2070 * @since 1.4
2071 */
2072 public void setClassAssertionStatus(String className, boolean enabled) {
2073 synchronized (assertionLock) {
2074 if (classAssertionStatus == null)
2075 initializeJavaAssertionMaps();
2076
2077 classAssertionStatus.put(className, enabled);
2078 }
2079 }
2080
2081 /**
2082 * Sets the default assertion status for this class loader to
2083 * <tt>false</tt> and discards any package defaults or class assertion
2084 * status settings associated with the class loader. This method is
2085 * provided so that class loaders can be made to ignore any command line or
2086 * persistent assertion status settings and "start with a clean slate."
2087 *
2088 * @since 1.4
2089 */
2090 public void clearAssertionStatus() {
2091 /*
2092 * Whether or not "Java assertion maps" are initialized, set
2093 * them to empty maps, effectively ignoring any present settings.
2094 */
2095 synchronized (assertionLock) {
2096 classAssertionStatus = new HashMap<>();
2097 packageAssertionStatus = new HashMap<>();
2098 defaultAssertionStatus = false;
2099 }
2100 }
2101
2102 /**
2103 * Returns the assertion status that would be assigned to the specified
2104 * class if it were to be initialized at the time this method is invoked.
2105 * If the named class has had its assertion status set, the most recent
2106 * setting will be returned; otherwise, if any package default assertion
2107 * status pertains to this class, the most recent setting for the most
2108 * specific pertinent package default assertion status is returned;
2109 * otherwise, this class loader's default assertion status is returned.
2110 * </p>
2111 *
2112 * @param className
2113 * The fully qualified class name of the class whose desired
2114 * assertion status is being queried.
2115 *
2116 * @return The desired assertion status of the specified class.
2117 *
2118 * @see #setClassAssertionStatus(String, boolean)
2119 * @see #setPackageAssertionStatus(String, boolean)
2120 * @see #setDefaultAssertionStatus(boolean)
2121 *
2122 * @since 1.4
2123 */
2124 boolean desiredAssertionStatus(String className) {
2125 synchronized (assertionLock) {
2126 // assert classAssertionStatus != null;
2127 // assert packageAssertionStatus != null;
2128
2129 // Check for a class entry
2130 Boolean result = classAssertionStatus.get(className);
2131 if (result != null)
2132 return result.booleanValue();
2133
2134 // Check for most specific package entry
2135 int dotIndex = className.lastIndexOf('.');
2136 if (dotIndex < 0) { // default package
2137 result = packageAssertionStatus.get(null);
2138 if (result != null)
2139 return result.booleanValue();
2140 }
2141 while(dotIndex > 0) {
2142 className = className.substring(0, dotIndex);
2143 result = packageAssertionStatus.get(className);
2144 if (result != null)
2145 return result.booleanValue();
2146 dotIndex = className.lastIndexOf('.', dotIndex-1);
2147 }
2148
2149 // Return the classloader default
2150 return defaultAssertionStatus;
2151 }
2152 }
2153
2154 // Set up the assertions with information provided by the VM.
2155 // Note: Should only be called inside a synchronized block
2156 private void initializeJavaAssertionMaps() {
2157 // assert Thread.holdsLock(assertionLock);
2158
2159 classAssertionStatus = new HashMap<>();
2160 packageAssertionStatus = new HashMap<>();
2161 AssertionStatusDirectives directives = retrieveDirectives();
2162
2163 for(int i = 0; i < directives.classes.length; i++)
2164 classAssertionStatus.put(directives.classes[i],
2165 directives.classEnabled[i]);
2166
2167 for(int i = 0; i < directives.packages.length; i++)
2168 packageAssertionStatus.put(directives.packages[i],
2169 directives.packageEnabled[i]);
2170
2171 defaultAssertionStatus = directives.deflt;
2172 }
2173
2174 // Retrieves the assertion directives from the VM.
2175 private static native AssertionStatusDirectives retrieveDirectives();
2176 }
2177
2178
2179 class SystemClassLoaderAction
2180 implements PrivilegedExceptionAction<ClassLoader> {
2181 private ClassLoader parent;
2182
2183 SystemClassLoaderAction(ClassLoader parent) {
2184 this.parent = parent;
2185 }
2186
2187 public ClassLoader run() throws Exception {
2188 String cls = System.getProperty("java.system.class.loader");
2189 if (cls == null) {
2190 return parent;
2191 }
2192
2193 Constructor<?> ctor = Class.forName(cls, true, parent)
2194 .getDeclaredConstructor(new Class<?>[] { ClassLoader.class });
2195 ClassLoader sys = (ClassLoader) ctor.newInstance(
2196 new Object[] { parent });
2197 Thread.currentThread().setContextClassLoader(sys);
2198 return sys;
2199 }
2200 }