1 /* 2 * Copyright (c) 1994, 2011, 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<>(); 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 = new HashMap<>(); 270 271 private static Void checkCreateClassLoader() { 272 SecurityManager security = System.getSecurityManager(); 273 if (security != null) { 274 security.checkCreateClassLoader(); 275 } 276 return null; 277 } 278 279 private ClassLoader(Void unused, ClassLoader parent) { 280 this.parent = parent; 281 if (ParallelLoaders.isRegistered(this.getClass())) { 282 parallelLockMap = new ConcurrentHashMap<>(); 283 package2certs = new ConcurrentHashMap<>(); 284 domains = 285 Collections.synchronizedSet(new HashSet<ProtectionDomain>()); 286 assertionLock = new Object(); 287 } else { 288 // no finer-grained lock; lock on the classloader instance 289 parallelLockMap = null; 290 package2certs = new Hashtable<>(); 291 domains = new HashSet<>(); 292 assertionLock = this; 293 } 294 } 295 296 /** 297 * Creates a new class loader using the specified parent class loader for 298 * delegation. 299 * 300 * <p> If there is a security manager, its {@link 301 * SecurityManager#checkCreateClassLoader() 302 * <tt>checkCreateClassLoader</tt>} method is invoked. This may result in 303 * a security exception. </p> 304 * 305 * @param parent 306 * The parent class loader 307 * 308 * @throws SecurityException 309 * If a security manager exists and its 310 * <tt>checkCreateClassLoader</tt> method doesn't allow creation 311 * of a new class loader. 312 * 313 * @since 1.2 314 */ 315 protected ClassLoader(ClassLoader parent) { 316 this(checkCreateClassLoader(), parent); 317 } 318 319 /** 320 * Creates a new class loader using the <tt>ClassLoader</tt> returned by 321 * the method {@link #getSystemClassLoader() 322 * <tt>getSystemClassLoader()</tt>} as the parent class loader. 323 * 324 * <p> If there is a security manager, its {@link 325 * SecurityManager#checkCreateClassLoader() 326 * <tt>checkCreateClassLoader</tt>} method is invoked. This may result in 327 * a security exception. </p> 328 * 329 * @throws SecurityException 330 * If a security manager exists and its 331 * <tt>checkCreateClassLoader</tt> method doesn't allow creation 332 * of a new class loader. 333 */ 334 protected ClassLoader() { 335 this(checkCreateClassLoader(), getSystemClassLoader()); 336 } 337 338 // -- Class -- 339 340 /** 341 * Loads the class with the specified <a href="#name">binary name</a>. 342 * This method searches for classes in the same manner as the {@link 343 * #loadClass(String, boolean)} method. It is invoked by the Java virtual 344 * machine to resolve class references. Invoking this method is equivalent 345 * to invoking {@link #loadClass(String, boolean) <tt>loadClass(name, 346 * false)</tt>}. </p> 347 * 348 * @param name 349 * The <a href="#name">binary name</a> of the class 350 * 351 * @return The resulting <tt>Class</tt> object 352 * 353 * @throws ClassNotFoundException 354 * If the class was not found 355 */ 356 public Class<?> loadClass(String name) throws ClassNotFoundException { 357 return loadClass(name, false); 358 } 359 360 /** 361 * Loads the class with the specified <a href="#name">binary name</a>. The 362 * default implementation of this method searches for classes in the 363 * following order: 364 * 365 * <p><ol> 366 * 367 * <li><p> Invoke {@link #findLoadedClass(String)} to check if the class 368 * has already been loaded. </p></li> 369 * 370 * <li><p> Invoke the {@link #loadClass(String) <tt>loadClass</tt>} method 371 * on the parent class loader. If the parent is <tt>null</tt> the class 372 * loader built-in to the virtual machine is used, instead. </p></li> 373 * 374 * <li><p> Invoke the {@link #findClass(String)} method to find the 375 * class. </p></li> 376 * 377 * </ol> 378 * 379 * <p> If the class was found using the above steps, and the 380 * <tt>resolve</tt> flag is true, this method will then invoke the {@link 381 * #resolveClass(Class)} method on the resulting <tt>Class</tt> object. 382 * 383 * <p> Subclasses of <tt>ClassLoader</tt> are encouraged to override {@link 384 * #findClass(String)}, rather than this method. </p> 385 * 386 * <p> Unless overridden, this method synchronizes on the result of 387 * {@link #getClassLoadingLock <tt>getClassLoadingLock</tt>} method 388 * during the entire class loading process. 389 * 390 * @param name 391 * The <a href="#name">binary name</a> of the class 392 * 393 * @param resolve 394 * If <tt>true</tt> then resolve the class 395 * 396 * @return The resulting <tt>Class</tt> object 397 * 398 * @throws ClassNotFoundException 399 * If the class could not be found 400 */ 401 protected Class<?> loadClass(String name, boolean resolve) 402 throws ClassNotFoundException 403 { 404 synchronized (getClassLoadingLock(name)) { 405 // First, check if the class has already been loaded 406 Class c = findLoadedClass(name); 407 if (c == null) { 408 long t0 = System.nanoTime(); 409 try { 410 if (parent != null) { 411 c = parent.loadClass(name, false); 412 } else { 413 c = findBootstrapClassOrNull(name); 414 } 415 } catch (ClassNotFoundException e) { 416 // ClassNotFoundException thrown if class not found 417 // from the non-null parent class loader 418 } 419 420 if (c == null) { 421 // If still not found, then invoke findClass in order 422 // to find the class. 423 long t1 = System.nanoTime(); 424 c = findClass(name); 425 426 // this is the defining class loader; record the stats 427 sun.misc.PerfCounter.getParentDelegationTime().addTime(t1 - t0); 428 sun.misc.PerfCounter.getFindClassTime().addElapsedTimeFrom(t1); 429 sun.misc.PerfCounter.getFindClasses().increment(); 430 } 431 } 432 if (resolve) { 433 resolveClass(c); 434 } 435 return c; 436 } 437 } 438 439 /** 440 * Returns the lock object for class loading operations. 441 * For backward compatibility, the default implementation of this method 442 * behaves as follows. If this ClassLoader object is registered as 443 * parallel capable, the method returns a dedicated object associated 444 * with the specified class name. Otherwise, the method returns this 445 * ClassLoader object. </p> 446 * 447 * @param className 448 * The name of the to-be-loaded class 449 * 450 * @return the lock for class loading operations 451 * 452 * @throws NullPointerException 453 * If registered as parallel capable and <tt>className</tt> is null 454 * 455 * @see #loadClass(String, boolean) 456 * 457 * @since 1.7 458 */ 459 protected Object getClassLoadingLock(String className) { 460 Object lock = this; 461 if (parallelLockMap != null) { 462 Object newLock = new Object(); 463 lock = parallelLockMap.putIfAbsent(className, newLock); 464 if (lock == null) { 465 lock = newLock; 466 } 467 } 468 return lock; 469 } 470 471 // This method is invoked by the virtual machine to load a class. 472 private Class loadClassInternal(String name) 473 throws ClassNotFoundException 474 { 475 // For backward compatibility, explicitly lock on 'this' when 476 // the current class loader is not parallel capable. 477 if (parallelLockMap == null) { 478 synchronized (this) { 479 return loadClass(name); 480 } 481 } else { 482 return loadClass(name); 483 } 484 } 485 486 // Invoked by the VM after loading class with this loader. 487 private void checkPackageAccess(Class cls, ProtectionDomain pd) { 488 final SecurityManager sm = System.getSecurityManager(); 489 if (sm != null) { 490 final String name = cls.getName(); 491 final int i = name.lastIndexOf('.'); 492 if (i != -1) { 493 AccessController.doPrivileged(new PrivilegedAction<Void>() { 494 public Void run() { 495 sm.checkPackageAccess(name.substring(0, i)); 496 return null; 497 } 498 }, new AccessControlContext(new ProtectionDomain[] {pd})); 499 } 500 } 501 domains.add(pd); 502 } 503 504 /** 505 * Finds the class with the specified <a href="#name">binary name</a>. 506 * This method should be overridden by class loader implementations that 507 * follow the delegation model for loading classes, and will be invoked by 508 * the {@link #loadClass <tt>loadClass</tt>} method after checking the 509 * parent class loader for the requested class. The default implementation 510 * throws a <tt>ClassNotFoundException</tt>. </p> 511 * 512 * @param name 513 * The <a href="#name">binary name</a> of the class 514 * 515 * @return The resulting <tt>Class</tt> object 516 * 517 * @throws ClassNotFoundException 518 * If the class could not be found 519 * 520 * @since 1.2 521 */ 522 protected Class<?> findClass(String name) throws ClassNotFoundException { 523 throw new ClassNotFoundException(name); 524 } 525 526 /** 527 * Converts an array of bytes into an instance of class <tt>Class</tt>. 528 * Before the <tt>Class</tt> can be used it must be resolved. This method 529 * is deprecated in favor of the version that takes a <a 530 * href="#name">binary name</a> as its first argument, and is more secure. 531 * 532 * @param b 533 * The bytes that make up the class data. The bytes in positions 534 * <tt>off</tt> through <tt>off+len-1</tt> should have the format 535 * of a valid class file as defined by the <a 536 * href="http://java.sun.com/docs/books/vmspec/">Java Virtual 537 * Machine Specification</a>. 538 * 539 * @param off 540 * The start offset in <tt>b</tt> of the class data 541 * 542 * @param len 543 * The length of the class data 544 * 545 * @return The <tt>Class</tt> object that was created from the specified 546 * class data 547 * 548 * @throws ClassFormatError 549 * If the data did not contain a valid class 550 * 551 * @throws IndexOutOfBoundsException 552 * If either <tt>off</tt> or <tt>len</tt> is negative, or if 553 * <tt>off+len</tt> is greater than <tt>b.length</tt>. 554 * 555 * @throws SecurityException 556 * If an attempt is made to add this class to a package that 557 * contains classes that were signed by a different set of 558 * certificates than this class, or if an attempt is made 559 * to define a class in a package with a fully-qualified name 560 * that starts with "{@code java.}". 561 * 562 * @see #loadClass(String, boolean) 563 * @see #resolveClass(Class) 564 * 565 * @deprecated Replaced by {@link #defineClass(String, byte[], int, int) 566 * defineClass(String, byte[], int, int)} 567 */ 568 @Deprecated 569 protected final Class<?> defineClass(byte[] b, int off, int len) 570 throws ClassFormatError 571 { 572 return defineClass(null, b, off, len, null); 573 } 574 575 /** 576 * Converts an array of bytes into an instance of class <tt>Class</tt>. 577 * Before the <tt>Class</tt> can be used it must be resolved. 578 * 579 * <p> This method assigns a default {@link java.security.ProtectionDomain 580 * <tt>ProtectionDomain</tt>} to the newly defined class. The 581 * <tt>ProtectionDomain</tt> is effectively granted the same set of 582 * permissions returned when {@link 583 * java.security.Policy#getPermissions(java.security.CodeSource) 584 * <tt>Policy.getPolicy().getPermissions(new CodeSource(null, null))</tt>} 585 * is invoked. The default domain is created on the first invocation of 586 * {@link #defineClass(String, byte[], int, int) <tt>defineClass</tt>}, 587 * and re-used on subsequent invocations. 588 * 589 * <p> To assign a specific <tt>ProtectionDomain</tt> to the class, use 590 * the {@link #defineClass(String, byte[], int, int, 591 * java.security.ProtectionDomain) <tt>defineClass</tt>} method that takes a 592 * <tt>ProtectionDomain</tt> as one of its arguments. </p> 593 * 594 * @param name 595 * The expected <a href="#name">binary name</a> of the class, or 596 * <tt>null</tt> if not known 597 * 598 * @param b 599 * The bytes that make up the class data. The bytes in positions 600 * <tt>off</tt> through <tt>off+len-1</tt> should have the format 601 * of a valid class file as defined by the <a 602 * href="http://java.sun.com/docs/books/vmspec/">Java Virtual 603 * Machine Specification</a>. 604 * 605 * @param off 606 * The start offset in <tt>b</tt> of the class data 607 * 608 * @param len 609 * The length of the class data 610 * 611 * @return The <tt>Class</tt> object that was created from the specified 612 * class data. 613 * 614 * @throws ClassFormatError 615 * If the data did not contain a valid class 616 * 617 * @throws IndexOutOfBoundsException 618 * If either <tt>off</tt> or <tt>len</tt> is negative, or if 619 * <tt>off+len</tt> is greater than <tt>b.length</tt>. 620 * 621 * @throws SecurityException 622 * If an attempt is made to add this class to a package that 623 * contains classes that were signed by a different set of 624 * certificates than this class (which is unsigned), or if 625 * <tt>name</tt> begins with "<tt>java.</tt>". 626 * 627 * @see #loadClass(String, boolean) 628 * @see #resolveClass(Class) 629 * @see java.security.CodeSource 630 * @see java.security.SecureClassLoader 631 * 632 * @since 1.1 633 */ 634 protected final Class<?> defineClass(String name, byte[] b, int off, int len) 635 throws ClassFormatError 636 { 637 return defineClass(name, b, off, len, null); 638 } 639 640 /* Determine protection domain, and check that: 641 - not define java.* class, 642 - signer of this class matches signers for the rest of the classes in 643 package. 644 */ 645 private ProtectionDomain preDefineClass(String name, 646 ProtectionDomain pd) 647 { 648 if (!checkName(name)) 649 throw new NoClassDefFoundError("IllegalName: " + name); 650 651 if ((name != null) && name.startsWith("java.")) { 652 throw new SecurityException 653 ("Prohibited package name: " + 654 name.substring(0, name.lastIndexOf('.'))); 655 } 656 if (pd == null) { 657 pd = defaultDomain; 658 } 659 660 if (name != null) checkCerts(name, pd.getCodeSource()); 661 662 return pd; 663 } 664 665 private String defineClassSourceLocation(ProtectionDomain pd) 666 { 667 CodeSource cs = pd.getCodeSource(); 668 String source = null; 669 if (cs != null && cs.getLocation() != null) { 670 source = cs.getLocation().toString(); 671 } 672 return source; 673 } 674 675 private Class defineTransformedClass(String name, byte[] b, int off, int len, 676 ProtectionDomain pd, 677 ClassFormatError cfe, String source) 678 throws ClassFormatError 679 { 680 // Class format error - try to transform the bytecode and 681 // define the class again 682 // 683 ClassFileTransformer[] transformers = 684 ClassFileTransformer.getTransformers(); 685 Class c = null; 686 687 if (transformers != null) { 688 for (ClassFileTransformer transformer : transformers) { 689 try { 690 // Transform byte code using transformer 691 byte[] tb = transformer.transform(b, off, len); 692 c = defineClass1(name, tb, 0, tb.length, 693 pd, source); 694 break; 695 } catch (ClassFormatError cfe2) { 696 // If ClassFormatError occurs, try next transformer 697 } 698 } 699 } 700 701 // Rethrow original ClassFormatError if unable to transform 702 // bytecode to well-formed 703 // 704 if (c == null) 705 throw cfe; 706 707 return c; 708 } 709 710 private void postDefineClass(Class c, ProtectionDomain pd) 711 { 712 if (pd.getCodeSource() != null) { 713 Certificate certs[] = pd.getCodeSource().getCertificates(); 714 if (certs != null) 715 setSigners(c, certs); 716 } 717 } 718 719 /** 720 * Converts an array of bytes into an instance of class <tt>Class</tt>, 721 * with an optional <tt>ProtectionDomain</tt>. If the domain is 722 * <tt>null</tt>, then a default domain will be assigned to the class as 723 * specified in the documentation for {@link #defineClass(String, byte[], 724 * int, int)}. Before the class can be used it must be resolved. 725 * 726 * <p> The first class defined in a package determines the exact set of 727 * certificates that all subsequent classes defined in that package must 728 * contain. The set of certificates for a class is obtained from the 729 * {@link java.security.CodeSource <tt>CodeSource</tt>} within the 730 * <tt>ProtectionDomain</tt> of the class. Any classes added to that 731 * package must contain the same set of certificates or a 732 * <tt>SecurityException</tt> will be thrown. Note that if 733 * <tt>name</tt> is <tt>null</tt>, this check is not performed. 734 * You should always pass in the <a href="#name">binary name</a> of the 735 * class you are defining as well as the bytes. This ensures that the 736 * class you are defining is indeed the class you think it is. 737 * 738 * <p> The specified <tt>name</tt> cannot begin with "<tt>java.</tt>", since 739 * all classes in the "<tt>java.*</tt> packages can only be defined by the 740 * bootstrap class loader. If <tt>name</tt> is not <tt>null</tt>, it 741 * must be equal to the <a href="#name">binary name</a> of the class 742 * specified by the byte array "<tt>b</tt>", otherwise a {@link 743 * <tt>NoClassDefFoundError</tt>} will be thrown. </p> 744 * 745 * @param name 746 * The expected <a href="#name">binary name</a> of the class, or 747 * <tt>null</tt> if not known 748 * 749 * @param b 750 * The bytes that make up the class data. The bytes in positions 751 * <tt>off</tt> through <tt>off+len-1</tt> should have the format 752 * of a valid class file as defined by the <a 753 * href="http://java.sun.com/docs/books/vmspec/">Java Virtual 754 * Machine Specification</a>. 755 * 756 * @param off 757 * The start offset in <tt>b</tt> of the class data 758 * 759 * @param len 760 * The length of the class data 761 * 762 * @param protectionDomain 763 * The ProtectionDomain of the class 764 * 765 * @return The <tt>Class</tt> object created from the data, 766 * and optional <tt>ProtectionDomain</tt>. 767 * 768 * @throws ClassFormatError 769 * If the data did not contain a valid class 770 * 771 * @throws NoClassDefFoundError 772 * If <tt>name</tt> is not equal to the <a href="#name">binary 773 * name</a> of the class specified by <tt>b</tt> 774 * 775 * @throws IndexOutOfBoundsException 776 * If either <tt>off</tt> or <tt>len</tt> is negative, or if 777 * <tt>off+len</tt> is greater than <tt>b.length</tt>. 778 * 779 * @throws SecurityException 780 * If an attempt is made to add this class to a package that 781 * contains classes that were signed by a different set of 782 * certificates than this class, or if <tt>name</tt> begins with 783 * "<tt>java.</tt>". 784 */ 785 protected final Class<?> defineClass(String name, byte[] b, int off, int len, 786 ProtectionDomain protectionDomain) 787 throws ClassFormatError 788 { 789 protectionDomain = preDefineClass(name, protectionDomain); 790 791 Class c = null; 792 String source = defineClassSourceLocation(protectionDomain); 793 794 try { 795 c = defineClass1(name, b, off, len, protectionDomain, source); 796 } catch (ClassFormatError cfe) { 797 c = defineTransformedClass(name, b, off, len, protectionDomain, cfe, 798 source); 799 } 800 801 postDefineClass(c, protectionDomain); 802 return c; 803 } 804 805 /** 806 * Converts a {@link java.nio.ByteBuffer <tt>ByteBuffer</tt>} 807 * into an instance of class <tt>Class</tt>, 808 * with an optional <tt>ProtectionDomain</tt>. If the domain is 809 * <tt>null</tt>, then a default domain will be assigned to the class as 810 * specified in the documentation for {@link #defineClass(String, byte[], 811 * int, int)}. Before the class can be used it must be resolved. 812 * 813 * <p>The rules about the first class defined in a package determining the 814 * set of certificates for the package, and the restrictions on class names 815 * are identical to those specified in the documentation for {@link 816 * #defineClass(String, byte[], int, int, ProtectionDomain)}. 817 * 818 * <p> An invocation of this method of the form 819 * <i>cl</i><tt>.defineClass(</tt><i>name</i><tt>,</tt> 820 * <i>bBuffer</i><tt>,</tt> <i>pd</i><tt>)</tt> yields exactly the same 821 * result as the statements 822 * 823 * <blockquote><tt> 824 * ...<br> 825 * byte[] temp = new byte[</tt><i>bBuffer</i><tt>.{@link 826 * java.nio.ByteBuffer#remaining remaining}()];<br> 827 * </tt><i>bBuffer</i><tt>.{@link java.nio.ByteBuffer#get(byte[]) 828 * get}(temp);<br> 829 * return {@link #defineClass(String, byte[], int, int, ProtectionDomain) 830 * </tt><i>cl</i><tt>.defineClass}(</tt><i>name</i><tt>, temp, 0, 831 * temp.length, </tt><i>pd</i><tt>);<br> 832 * </tt></blockquote> 833 * 834 * @param name 835 * The expected <a href="#name">binary name</a>. of the class, or 836 * <tt>null</tt> if not known 837 * 838 * @param b 839 * The bytes that make up the class data. The bytes from positions 840 * <tt>b.position()</tt> through <tt>b.position() + b.limit() -1 841 * </tt> should have the format of a valid class file as defined by 842 * the <a href="http://java.sun.com/docs/books/vmspec/">Java Virtual 843 * Machine Specification</a>. 844 * 845 * @param protectionDomain 846 * The ProtectionDomain of the class, or <tt>null</tt>. 847 * 848 * @return The <tt>Class</tt> object created from the data, 849 * and optional <tt>ProtectionDomain</tt>. 850 * 851 * @throws ClassFormatError 852 * If the data did not contain a valid class. 853 * 854 * @throws NoClassDefFoundError 855 * If <tt>name</tt> is not equal to the <a href="#name">binary 856 * name</a> of the class specified by <tt>b</tt> 857 * 858 * @throws SecurityException 859 * If an attempt is made to add this class to a package that 860 * contains classes that were signed by a different set of 861 * certificates than this class, or if <tt>name</tt> begins with 862 * "<tt>java.</tt>". 863 * 864 * @see #defineClass(String, byte[], int, int, ProtectionDomain) 865 * 866 * @since 1.5 867 */ 868 protected final Class<?> defineClass(String name, java.nio.ByteBuffer b, 869 ProtectionDomain protectionDomain) 870 throws ClassFormatError 871 { 872 int len = b.remaining(); 873 874 // Use byte[] if not a direct ByteBufer: 875 if (!b.isDirect()) { 876 if (b.hasArray()) { 877 return defineClass(name, b.array(), 878 b.position() + b.arrayOffset(), len, 879 protectionDomain); 880 } else { 881 // no array, or read-only array 882 byte[] tb = new byte[len]; 883 b.get(tb); // get bytes out of byte buffer. 884 return defineClass(name, tb, 0, len, protectionDomain); 885 } 886 } 887 888 protectionDomain = preDefineClass(name, protectionDomain); 889 890 Class c = null; 891 String source = defineClassSourceLocation(protectionDomain); 892 893 try { 894 c = defineClass2(name, b, b.position(), len, protectionDomain, 895 source); 896 } catch (ClassFormatError cfe) { 897 byte[] tb = new byte[len]; 898 b.get(tb); // get bytes out of byte buffer. 899 c = defineTransformedClass(name, tb, 0, len, protectionDomain, cfe, 900 source); 901 } 902 903 postDefineClass(c, protectionDomain); 904 return c; 905 } 906 907 private native Class defineClass0(String name, byte[] b, int off, int len, 908 ProtectionDomain pd); 909 910 private native Class defineClass1(String name, byte[] b, int off, int len, 911 ProtectionDomain pd, String source); 912 913 private native Class defineClass2(String name, java.nio.ByteBuffer b, 914 int off, int len, ProtectionDomain pd, 915 String source); 916 917 // true if the name is null or has the potential to be a valid binary name 918 private boolean checkName(String name) { 919 if ((name == null) || (name.length() == 0)) 920 return true; 921 if ((name.indexOf('/') != -1) 922 || (!VM.allowArraySyntax() && (name.charAt(0) == '['))) 923 return false; 924 return true; 925 } 926 927 private void checkCerts(String name, CodeSource cs) { 928 int i = name.lastIndexOf('.'); 929 String pname = (i == -1) ? "" : name.substring(0, i); 930 931 Certificate[] certs = null; 932 if (cs != null) { 933 certs = cs.getCertificates(); 934 } 935 Certificate[] pcerts = null; 936 if (parallelLockMap == null) { 937 synchronized (this) { 938 pcerts = package2certs.get(pname); 939 if (pcerts == null) { 940 package2certs.put(pname, (certs == null? nocerts:certs)); 941 } 942 } 943 } else { 944 pcerts = ((ConcurrentHashMap<String, Certificate[]>)package2certs). 945 putIfAbsent(pname, (certs == null? nocerts:certs)); 946 } 947 if (pcerts != null && !compareCerts(pcerts, certs)) { 948 throw new SecurityException("class \""+ name + 949 "\"'s signer information does not match signer information of other classes in the same package"); 950 } 951 } 952 953 /** 954 * check to make sure the certs for the new class (certs) are the same as 955 * the certs for the first class inserted in the package (pcerts) 956 */ 957 private boolean compareCerts(Certificate[] pcerts, 958 Certificate[] certs) 959 { 960 // certs can be null, indicating no certs. 961 if ((certs == null) || (certs.length == 0)) { 962 return pcerts.length == 0; 963 } 964 965 // the length must be the same at this point 966 if (certs.length != pcerts.length) 967 return false; 968 969 // go through and make sure all the certs in one array 970 // are in the other and vice-versa. 971 boolean match; 972 for (int i = 0; i < certs.length; i++) { 973 match = false; 974 for (int j = 0; j < pcerts.length; j++) { 975 if (certs[i].equals(pcerts[j])) { 976 match = true; 977 break; 978 } 979 } 980 if (!match) return false; 981 } 982 983 // now do the same for pcerts 984 for (int i = 0; i < pcerts.length; i++) { 985 match = false; 986 for (int j = 0; j < certs.length; j++) { 987 if (pcerts[i].equals(certs[j])) { 988 match = true; 989 break; 990 } 991 } 992 if (!match) return false; 993 } 994 995 return true; 996 } 997 998 /** 999 * Links the specified class. This (misleadingly named) method may be 1000 * used by a class loader to link a class. If the class <tt>c</tt> has 1001 * already been linked, then this method simply returns. Otherwise, the 1002 * class is linked as described in the "Execution" chapter of the <a 1003 * href="http://java.sun.com/docs/books/jls/">Java Language 1004 * Specification</a>. 1005 * </p> 1006 * 1007 * @param c 1008 * The class to link 1009 * 1010 * @throws NullPointerException 1011 * If <tt>c</tt> is <tt>null</tt>. 1012 * 1013 * @see #defineClass(String, byte[], int, int) 1014 */ 1015 protected final void resolveClass(Class<?> c) { 1016 resolveClass0(c); 1017 } 1018 1019 private native void resolveClass0(Class c); 1020 1021 /** 1022 * Finds a class with the specified <a href="#name">binary name</a>, 1023 * loading it if necessary. 1024 * 1025 * <p> This method loads the class through the system class loader (see 1026 * {@link #getSystemClassLoader()}). The <tt>Class</tt> object returned 1027 * might have more than one <tt>ClassLoader</tt> associated with it. 1028 * Subclasses of <tt>ClassLoader</tt> need not usually invoke this method, 1029 * because most class loaders need to override just {@link 1030 * #findClass(String)}. </p> 1031 * 1032 * @param name 1033 * The <a href="#name">binary name</a> of the class 1034 * 1035 * @return The <tt>Class</tt> object for the specified <tt>name</tt> 1036 * 1037 * @throws ClassNotFoundException 1038 * If the class could not be found 1039 * 1040 * @see #ClassLoader(ClassLoader) 1041 * @see #getParent() 1042 */ 1043 protected final Class<?> findSystemClass(String name) 1044 throws ClassNotFoundException 1045 { 1046 ClassLoader system = getSystemClassLoader(); 1047 if (system == null) { 1048 if (!checkName(name)) 1049 throw new ClassNotFoundException(name); 1050 Class cls = findBootstrapClass(name); 1051 if (cls == null) { 1052 throw new ClassNotFoundException(name); 1053 } 1054 return cls; 1055 } 1056 return system.loadClass(name); 1057 } 1058 1059 /** 1060 * Returns a class loaded by the bootstrap class loader; 1061 * or return null if not found. 1062 */ 1063 private Class findBootstrapClassOrNull(String name) 1064 { 1065 if (!checkName(name)) return null; 1066 1067 return findBootstrapClass(name); 1068 } 1069 1070 // return null if not found 1071 private native Class findBootstrapClass(String name); 1072 1073 /** 1074 * Returns the class with the given <a href="#name">binary name</a> if this 1075 * loader has been recorded by the Java virtual machine as an initiating 1076 * loader of a class with that <a href="#name">binary name</a>. Otherwise 1077 * <tt>null</tt> is returned. </p> 1078 * 1079 * @param name 1080 * The <a href="#name">binary name</a> of the class 1081 * 1082 * @return The <tt>Class</tt> object, or <tt>null</tt> if the class has 1083 * not been loaded 1084 * 1085 * @since 1.1 1086 */ 1087 protected final Class<?> findLoadedClass(String name) { 1088 if (!checkName(name)) 1089 return null; 1090 return findLoadedClass0(name); 1091 } 1092 1093 private native final Class findLoadedClass0(String name); 1094 1095 /** 1096 * Sets the signers of a class. This should be invoked after defining a 1097 * class. </p> 1098 * 1099 * @param c 1100 * The <tt>Class</tt> object 1101 * 1102 * @param signers 1103 * The signers for the class 1104 * 1105 * @since 1.1 1106 */ 1107 protected final void setSigners(Class<?> c, Object[] signers) { 1108 c.setSigners(signers); 1109 } 1110 1111 1112 // -- Resource -- 1113 1114 /** 1115 * Finds the resource with the given name. A resource is some data 1116 * (images, audio, text, etc) that can be accessed by class code in a way 1117 * that is independent of the location of the code. 1118 * 1119 * <p> The name of a resource is a '<tt>/</tt>'-separated path name that 1120 * identifies the resource. 1121 * 1122 * <p> This method will first search the parent class loader for the 1123 * resource; if the parent is <tt>null</tt> the path of the class loader 1124 * built-in to the virtual machine is searched. That failing, this method 1125 * will invoke {@link #findResource(String)} to find the resource. </p> 1126 * 1127 * @param name 1128 * The resource name 1129 * 1130 * @return A <tt>URL</tt> object for reading the resource, or 1131 * <tt>null</tt> if the resource could not be found or the invoker 1132 * doesn't have adequate privileges to get the resource. 1133 * 1134 * @since 1.1 1135 */ 1136 public URL getResource(String name) { 1137 URL url; 1138 if (parent != null) { 1139 url = parent.getResource(name); 1140 } else { 1141 url = getBootstrapResource(name); 1142 } 1143 if (url == null) { 1144 url = findResource(name); 1145 } 1146 return url; 1147 } 1148 1149 /** 1150 * Finds all the resources with the given name. A resource is some data 1151 * (images, audio, text, etc) that can be accessed by class code in a way 1152 * that is independent of the location of the code. 1153 * 1154 * <p>The name of a resource is a <tt>/</tt>-separated path name that 1155 * identifies the resource. 1156 * 1157 * <p> The search order is described in the documentation for {@link 1158 * #getResource(String)}. </p> 1159 * 1160 * @param name 1161 * The resource name 1162 * 1163 * @return An enumeration of {@link java.net.URL <tt>URL</tt>} objects for 1164 * the resource. If no resources could be found, the enumeration 1165 * will be empty. Resources that the class loader doesn't have 1166 * access to will not be in the enumeration. 1167 * 1168 * @throws IOException 1169 * If I/O errors occur 1170 * 1171 * @see #findResources(String) 1172 * 1173 * @since 1.2 1174 */ 1175 public Enumeration<URL> getResources(String name) throws IOException { 1176 Enumeration[] tmp = new Enumeration[2]; 1177 if (parent != null) { 1178 tmp[0] = parent.getResources(name); 1179 } else { 1180 tmp[0] = getBootstrapResources(name); 1181 } 1182 tmp[1] = findResources(name); 1183 1184 return new CompoundEnumeration<>(tmp); 1185 } 1186 1187 /** 1188 * Finds the resource with the given name. Class loader implementations 1189 * should override this method to specify where to find resources. </p> 1190 * 1191 * @param name 1192 * The resource name 1193 * 1194 * @return A <tt>URL</tt> object for reading the resource, or 1195 * <tt>null</tt> if the resource could not be found 1196 * 1197 * @since 1.2 1198 */ 1199 protected URL findResource(String name) { 1200 return null; 1201 } 1202 1203 /** 1204 * Returns an enumeration of {@link java.net.URL <tt>URL</tt>} objects 1205 * representing all the resources with the given name. Class loader 1206 * implementations should override this method to specify where to load 1207 * resources from. </p> 1208 * 1209 * @param name 1210 * The resource name 1211 * 1212 * @return An enumeration of {@link java.net.URL <tt>URL</tt>} objects for 1213 * the resources 1214 * 1215 * @throws IOException 1216 * If I/O errors occur 1217 * 1218 * @since 1.2 1219 */ 1220 protected Enumeration<URL> findResources(String name) throws IOException { 1221 return java.util.Collections.emptyEnumeration(); 1222 } 1223 1224 // index 0: java.lang.ClassLoader.class 1225 // index 1: the immediate caller of index 0. 1226 // index 2: the immediate caller of index 1. 1227 private static native Class<? extends ClassLoader> getCaller(int index); 1228 1229 /** 1230 * Registers the caller as parallel capable.</p> 1231 * The registration succeeds if and only if all of the following 1232 * conditions are met: <br> 1233 * 1. no instance of the caller has been created</p> 1234 * 2. all of the super classes (except class Object) of the caller are 1235 * registered as parallel capable</p> 1236 * Note that once a class loader is registered as parallel capable, there 1237 * is no way to change it back. </p> 1238 * 1239 * @return true if the caller is successfully registered as 1240 * parallel capable and false if otherwise. 1241 * 1242 * @since 1.7 1243 */ 1244 protected static boolean registerAsParallelCapable() { 1245 return ParallelLoaders.register(getCaller(1)); 1246 } 1247 1248 /** 1249 * Find a resource of the specified name from the search path used to load 1250 * classes. This method locates the resource through the system class 1251 * loader (see {@link #getSystemClassLoader()}). </p> 1252 * 1253 * @param name 1254 * The resource name 1255 * 1256 * @return A {@link java.net.URL <tt>URL</tt>} object for reading the 1257 * resource, or <tt>null</tt> if the resource could not be found 1258 * 1259 * @since 1.1 1260 */ 1261 public static URL getSystemResource(String name) { 1262 ClassLoader system = getSystemClassLoader(); 1263 if (system == null) { 1264 return getBootstrapResource(name); 1265 } 1266 return system.getResource(name); 1267 } 1268 1269 /** 1270 * Finds all resources of the specified name from the search path used to 1271 * load classes. The resources thus found are returned as an 1272 * {@link java.util.Enumeration <tt>Enumeration</tt>} of {@link 1273 * java.net.URL <tt>URL</tt>} objects. 1274 * 1275 * <p> The search order is described in the documentation for {@link 1276 * #getSystemResource(String)}. </p> 1277 * 1278 * @param name 1279 * The resource name 1280 * 1281 * @return An enumeration of resource {@link java.net.URL <tt>URL</tt>} 1282 * objects 1283 * 1284 * @throws IOException 1285 * If I/O errors occur 1286 1287 * @since 1.2 1288 */ 1289 public static Enumeration<URL> getSystemResources(String name) 1290 throws IOException 1291 { 1292 ClassLoader system = getSystemClassLoader(); 1293 if (system == null) { 1294 return getBootstrapResources(name); 1295 } 1296 return system.getResources(name); 1297 } 1298 1299 /** 1300 * Find resources from the VM's built-in classloader. 1301 */ 1302 private static URL getBootstrapResource(String name) { 1303 BootClassLoaderHook.preLoadResource(name); 1304 URLClassPath ucp = getBootstrapClassPath(); 1305 Resource res = ucp.getResource(name); 1306 return res != null ? res.getURL() : null; 1307 } 1308 1309 /** 1310 * Find resources from the VM's built-in classloader. 1311 */ 1312 private static Enumeration<URL> getBootstrapResources(String name) 1313 throws IOException 1314 { 1315 final Enumeration<Resource> e = 1316 getBootstrapClassPath().getResources(name); 1317 return new Enumeration<URL> () { 1318 public URL nextElement() { 1319 return e.nextElement().getURL(); 1320 } 1321 public boolean hasMoreElements() { 1322 return e.hasMoreElements(); 1323 } 1324 }; 1325 } 1326 1327 // Returns the URLClassPath that is used for finding system resources. 1328 static URLClassPath getBootstrapClassPath() { 1329 return sun.misc.Launcher.getBootstrapClassPath(); 1330 } 1331 1332 1333 /** 1334 * Returns an input stream for reading the specified resource. 1335 * 1336 * <p> The search order is described in the documentation for {@link 1337 * #getResource(String)}. </p> 1338 * 1339 * @param name 1340 * The resource name 1341 * 1342 * @return An input stream for reading the resource, or <tt>null</tt> 1343 * if the resource could not be found 1344 * 1345 * @since 1.1 1346 */ 1347 public InputStream getResourceAsStream(String name) { 1348 URL url = getResource(name); 1349 try { 1350 return url != null ? url.openStream() : null; 1351 } catch (IOException e) { 1352 return null; 1353 } 1354 } 1355 1356 /** 1357 * Open for reading, a resource of the specified name from the search path 1358 * used to load classes. This method locates the resource through the 1359 * system class loader (see {@link #getSystemClassLoader()}). </p> 1360 * 1361 * @param name 1362 * The resource name 1363 * 1364 * @return An input stream for reading the resource, or <tt>null</tt> 1365 * if the resource could not be found 1366 * 1367 * @since 1.1 1368 */ 1369 public static InputStream getSystemResourceAsStream(String name) { 1370 URL url = getSystemResource(name); 1371 try { 1372 return url != null ? url.openStream() : null; 1373 } catch (IOException e) { 1374 return null; 1375 } 1376 } 1377 1378 1379 // -- Hierarchy -- 1380 1381 /** 1382 * Returns the parent class loader for delegation. Some implementations may 1383 * use <tt>null</tt> to represent the bootstrap class loader. This method 1384 * will return <tt>null</tt> in such implementations if this class loader's 1385 * parent is the bootstrap class loader. 1386 * 1387 * <p> If a security manager is present, and the invoker's class loader is 1388 * not <tt>null</tt> and is not an ancestor of this class loader, then this 1389 * method invokes the security manager's {@link 1390 * SecurityManager#checkPermission(java.security.Permission) 1391 * <tt>checkPermission</tt>} method with a {@link 1392 * RuntimePermission#RuntimePermission(String) 1393 * <tt>RuntimePermission("getClassLoader")</tt>} permission to verify 1394 * access to the parent class loader is permitted. If not, a 1395 * <tt>SecurityException</tt> will be thrown. </p> 1396 * 1397 * @return The parent <tt>ClassLoader</tt> 1398 * 1399 * @throws SecurityException 1400 * If a security manager exists and its <tt>checkPermission</tt> 1401 * method doesn't allow access to this class loader's parent class 1402 * loader. 1403 * 1404 * @since 1.2 1405 */ 1406 public final ClassLoader getParent() { 1407 if (parent == null) 1408 return null; 1409 SecurityManager sm = System.getSecurityManager(); 1410 if (sm != null) { 1411 ClassLoader ccl = getCallerClassLoader(); 1412 if (ccl != null && !isAncestor(ccl)) { 1413 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION); 1414 } 1415 } 1416 return parent; 1417 } 1418 1419 /** 1420 * Returns the system class loader for delegation. This is the default 1421 * delegation parent for new <tt>ClassLoader</tt> instances, and is 1422 * typically the class loader used to start the application. 1423 * 1424 * <p> This method is first invoked early in the runtime's startup 1425 * sequence, at which point it creates the system class loader and sets it 1426 * as the context class loader of the invoking <tt>Thread</tt>. 1427 * 1428 * <p> The default system class loader is an implementation-dependent 1429 * instance of this class. 1430 * 1431 * <p> If the system property "<tt>java.system.class.loader</tt>" is defined 1432 * when this method is first invoked then the value of that property is 1433 * taken to be the name of a class that will be returned as the system 1434 * class loader. The class is loaded using the default system class loader 1435 * and must define a public constructor that takes a single parameter of 1436 * type <tt>ClassLoader</tt> which is used as the delegation parent. An 1437 * instance is then created using this constructor with the default system 1438 * class loader as the parameter. The resulting class loader is defined 1439 * to be the system class loader. 1440 * 1441 * <p> If a security manager is present, and the invoker's class loader is 1442 * not <tt>null</tt> and the invoker's class loader is not the same as or 1443 * an ancestor of the system class loader, then this method invokes the 1444 * security manager's {@link 1445 * SecurityManager#checkPermission(java.security.Permission) 1446 * <tt>checkPermission</tt>} method with a {@link 1447 * RuntimePermission#RuntimePermission(String) 1448 * <tt>RuntimePermission("getClassLoader")</tt>} permission to verify 1449 * access to the system class loader. If not, a 1450 * <tt>SecurityException</tt> will be thrown. </p> 1451 * 1452 * @return The system <tt>ClassLoader</tt> for delegation, or 1453 * <tt>null</tt> if none 1454 * 1455 * @throws SecurityException 1456 * If a security manager exists and its <tt>checkPermission</tt> 1457 * method doesn't allow access to the system class loader. 1458 * 1459 * @throws IllegalStateException 1460 * If invoked recursively during the construction of the class 1461 * loader specified by the "<tt>java.system.class.loader</tt>" 1462 * property. 1463 * 1464 * @throws Error 1465 * If the system property "<tt>java.system.class.loader</tt>" 1466 * is defined but the named class could not be loaded, the 1467 * provider class does not define the required constructor, or an 1468 * exception is thrown by that constructor when it is invoked. The 1469 * underlying cause of the error can be retrieved via the 1470 * {@link Throwable#getCause()} method. 1471 * 1472 * @revised 1.4 1473 */ 1474 public static ClassLoader getSystemClassLoader() { 1475 initSystemClassLoader(); 1476 if (scl == null) { 1477 return null; 1478 } 1479 SecurityManager sm = System.getSecurityManager(); 1480 if (sm != null) { 1481 ClassLoader ccl = getCallerClassLoader(); 1482 if (ccl != null && ccl != scl && !scl.isAncestor(ccl)) { 1483 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION); 1484 } 1485 } 1486 return scl; 1487 } 1488 1489 private static synchronized void initSystemClassLoader() { 1490 if (!sclSet) { 1491 if (scl != null) 1492 throw new IllegalStateException("recursive invocation"); 1493 sun.misc.Launcher l = sun.misc.Launcher.getLauncher(); 1494 if (l != null) { 1495 Throwable oops = null; 1496 scl = l.getClassLoader(); 1497 try { 1498 scl = AccessController.doPrivileged( 1499 new SystemClassLoaderAction(scl)); 1500 } catch (PrivilegedActionException pae) { 1501 oops = pae.getCause(); 1502 if (oops instanceof InvocationTargetException) { 1503 oops = oops.getCause(); 1504 } 1505 } 1506 if (oops != null) { 1507 if (oops instanceof Error) { 1508 throw (Error) oops; 1509 } else { 1510 // wrap the exception 1511 throw new Error(oops); 1512 } 1513 } 1514 } 1515 sclSet = true; 1516 } 1517 } 1518 1519 // Returns true if the specified class loader can be found in this class 1520 // loader's delegation chain. 1521 boolean isAncestor(ClassLoader cl) { 1522 ClassLoader acl = this; 1523 do { 1524 acl = acl.parent; 1525 if (cl == acl) { 1526 return true; 1527 } 1528 } while (acl != null); 1529 return false; 1530 } 1531 1532 // Returns the invoker's class loader, or null if none. 1533 // NOTE: This must always be invoked when there is exactly one intervening 1534 // frame from the core libraries on the stack between this method's 1535 // invocation and the desired invoker. 1536 static ClassLoader getCallerClassLoader() { 1537 // NOTE use of more generic Reflection.getCallerClass() 1538 Class caller = Reflection.getCallerClass(3); 1539 // This can be null if the VM is requesting it 1540 if (caller == null) { 1541 return null; 1542 } 1543 // Circumvent security check since this is package-private 1544 return caller.getClassLoader0(); 1545 } 1546 1547 // The class loader for the system 1548 // @GuardedBy("ClassLoader.class") 1549 private static ClassLoader scl; 1550 1551 // Set to true once the system class loader has been set 1552 // @GuardedBy("ClassLoader.class") 1553 private static boolean sclSet; 1554 1555 1556 // -- Package -- 1557 1558 /** 1559 * Defines a package by name in this <tt>ClassLoader</tt>. This allows 1560 * class loaders to define the packages for their classes. Packages must 1561 * be created before the class is defined, and package names must be 1562 * unique within a class loader and cannot be redefined or changed once 1563 * created. </p> 1564 * 1565 * @param name 1566 * The package name 1567 * 1568 * @param specTitle 1569 * The specification title 1570 * 1571 * @param specVersion 1572 * The specification version 1573 * 1574 * @param specVendor 1575 * The specification vendor 1576 * 1577 * @param implTitle 1578 * The implementation title 1579 * 1580 * @param implVersion 1581 * The implementation version 1582 * 1583 * @param implVendor 1584 * The implementation vendor 1585 * 1586 * @param sealBase 1587 * If not <tt>null</tt>, then this package is sealed with 1588 * respect to the given code source {@link java.net.URL 1589 * <tt>URL</tt>} object. Otherwise, the package is not sealed. 1590 * 1591 * @return The newly defined <tt>Package</tt> object 1592 * 1593 * @throws IllegalArgumentException 1594 * If package name duplicates an existing package either in this 1595 * class loader or one of its ancestors 1596 * 1597 * @since 1.2 1598 */ 1599 protected Package definePackage(String name, String specTitle, 1600 String specVersion, String specVendor, 1601 String implTitle, String implVersion, 1602 String implVendor, URL sealBase) 1603 throws IllegalArgumentException 1604 { 1605 synchronized (packages) { 1606 Package pkg = getPackage(name); 1607 if (pkg != null) { 1608 throw new IllegalArgumentException(name); 1609 } 1610 pkg = new Package(name, specTitle, specVersion, specVendor, 1611 implTitle, implVersion, implVendor, 1612 sealBase, this); 1613 packages.put(name, pkg); 1614 return pkg; 1615 } 1616 } 1617 1618 /** 1619 * Returns a <tt>Package</tt> that has been defined by this class loader 1620 * or any of its ancestors. </p> 1621 * 1622 * @param name 1623 * The package name 1624 * 1625 * @return The <tt>Package</tt> corresponding to the given name, or 1626 * <tt>null</tt> if not found 1627 * 1628 * @since 1.2 1629 */ 1630 protected Package getPackage(String name) { 1631 Package pkg; 1632 synchronized (packages) { 1633 pkg = packages.get(name); 1634 } 1635 if (pkg == null) { 1636 if (parent != null) { 1637 pkg = parent.getPackage(name); 1638 } else { 1639 pkg = Package.getSystemPackage(name); 1640 } 1641 if (pkg != null) { 1642 synchronized (packages) { 1643 Package pkg2 = packages.get(name); 1644 if (pkg2 == null) { 1645 packages.put(name, pkg); 1646 } else { 1647 pkg = pkg2; 1648 } 1649 } 1650 } 1651 } 1652 return pkg; 1653 } 1654 1655 /** 1656 * Returns all of the <tt>Packages</tt> defined by this class loader and 1657 * its ancestors. </p> 1658 * 1659 * @return The array of <tt>Package</tt> objects defined by this 1660 * <tt>ClassLoader</tt> 1661 * 1662 * @since 1.2 1663 */ 1664 protected Package[] getPackages() { 1665 Map<String, Package> map; 1666 synchronized (packages) { 1667 map = new HashMap<>(packages); 1668 } 1669 Package[] pkgs; 1670 if (parent != null) { 1671 pkgs = parent.getPackages(); 1672 } else { 1673 pkgs = Package.getSystemPackages(); 1674 } 1675 if (pkgs != null) { 1676 for (int i = 0; i < pkgs.length; i++) { 1677 String pkgName = pkgs[i].getName(); 1678 if (map.get(pkgName) == null) { 1679 map.put(pkgName, pkgs[i]); 1680 } 1681 } 1682 } 1683 return map.values().toArray(new Package[map.size()]); 1684 } 1685 1686 1687 // -- Native library access -- 1688 1689 /** 1690 * Returns the absolute path name of a native library. The VM invokes this 1691 * method to locate the native libraries that belong to classes loaded with 1692 * this class loader. If this method returns <tt>null</tt>, the VM 1693 * searches the library along the path specified as the 1694 * "<tt>java.library.path</tt>" property. </p> 1695 * 1696 * @param libname 1697 * The library name 1698 * 1699 * @return The absolute path of the native library 1700 * 1701 * @see System#loadLibrary(String) 1702 * @see System#mapLibraryName(String) 1703 * 1704 * @since 1.2 1705 */ 1706 protected String findLibrary(String libname) { 1707 return null; 1708 } 1709 1710 /** 1711 * The inner class NativeLibrary denotes a loaded native library instance. 1712 * Every classloader contains a vector of loaded native libraries in the 1713 * private field <tt>nativeLibraries</tt>. The native libraries loaded 1714 * into the system are entered into the <tt>systemNativeLibraries</tt> 1715 * vector. 1716 * 1717 * <p> Every native library requires a particular version of JNI. This is 1718 * denoted by the private <tt>jniVersion</tt> field. This field is set by 1719 * the VM when it loads the library, and used by the VM to pass the correct 1720 * version of JNI to the native methods. </p> 1721 * 1722 * @see ClassLoader 1723 * @since 1.2 1724 */ 1725 static class NativeLibrary { 1726 // opaque handle to native library, used in native code. 1727 long handle; 1728 // the version of JNI environment the native library requires. 1729 private int jniVersion; 1730 // the class from which the library is loaded, also indicates 1731 // the loader this native library belongs. 1732 private Class fromClass; 1733 // the canonicalized name of the native library. 1734 String name; 1735 1736 native void load(String name); 1737 native long find(String name); 1738 native void unload(); 1739 1740 public NativeLibrary(Class fromClass, String name) { 1741 this.name = name; 1742 this.fromClass = fromClass; 1743 } 1744 1745 protected void finalize() { 1746 synchronized (loadedLibraryNames) { 1747 if (fromClass.getClassLoader() != null && handle != 0) { 1748 /* remove the native library name */ 1749 int size = loadedLibraryNames.size(); 1750 for (int i = 0; i < size; i++) { 1751 if (name.equals(loadedLibraryNames.elementAt(i))) { 1752 loadedLibraryNames.removeElementAt(i); 1753 break; 1754 } 1755 } 1756 /* unload the library. */ 1757 ClassLoader.nativeLibraryContext.push(this); 1758 try { 1759 unload(); 1760 } finally { 1761 ClassLoader.nativeLibraryContext.pop(); 1762 } 1763 } 1764 } 1765 } 1766 // Invoked in the VM to determine the context class in 1767 // JNI_Load/JNI_Unload 1768 static Class getFromClass() { 1769 return ClassLoader.nativeLibraryContext.peek().fromClass; 1770 } 1771 } 1772 1773 // All native library names we've loaded. 1774 private static Vector<String> loadedLibraryNames = new Vector<>(); 1775 1776 // Native libraries belonging to system classes. 1777 private static Vector<NativeLibrary> systemNativeLibraries 1778 = new Vector<>(); 1779 1780 // Native libraries associated with the class loader. 1781 private Vector<NativeLibrary> nativeLibraries = new Vector<>(); 1782 1783 // native libraries being loaded/unloaded. 1784 private static Stack<NativeLibrary> nativeLibraryContext = new Stack<>(); 1785 1786 // The paths searched for libraries 1787 private static String usr_paths[]; 1788 private static String sys_paths[]; 1789 1790 private static String[] initializePath(String propname) { 1791 String ldpath = System.getProperty(propname, ""); 1792 String ps = File.pathSeparator; 1793 int ldlen = ldpath.length(); 1794 int i, j, n; 1795 // Count the separators in the path 1796 i = ldpath.indexOf(ps); 1797 n = 0; 1798 while (i >= 0) { 1799 n++; 1800 i = ldpath.indexOf(ps, i + 1); 1801 } 1802 1803 // allocate the array of paths - n :'s = n + 1 path elements 1804 String[] paths = new String[n + 1]; 1805 1806 // Fill the array with paths from the ldpath 1807 n = i = 0; 1808 j = ldpath.indexOf(ps); 1809 while (j >= 0) { 1810 if (j - i > 0) { 1811 paths[n++] = ldpath.substring(i, j); 1812 } else if (j - i == 0) { 1813 paths[n++] = "."; 1814 } 1815 i = j + 1; 1816 j = ldpath.indexOf(ps, i); 1817 } 1818 paths[n] = ldpath.substring(i, ldlen); 1819 return paths; 1820 } 1821 1822 // Invoked in the java.lang.Runtime class to implement load and loadLibrary. 1823 static void loadLibrary(Class fromClass, String name, 1824 boolean isAbsolute) { 1825 BootClassLoaderHook.preLoadLibrary(name); 1826 ClassLoader loader = 1827 (fromClass == null) ? null : fromClass.getClassLoader(); 1828 if (sys_paths == null) { 1829 usr_paths = initializePath("java.library.path"); 1830 sys_paths = initializePath("sun.boot.library.path"); 1831 } 1832 if (isAbsolute) { 1833 if (loadLibrary0(fromClass, new File(name))) { 1834 return; 1835 } 1836 throw new UnsatisfiedLinkError("Can't load library: " + name); 1837 } 1838 if (loader != null) { 1839 String libfilename = loader.findLibrary(name); 1840 if (libfilename != null) { 1841 File libfile = new File(libfilename); 1842 if (!libfile.isAbsolute()) { 1843 throw new UnsatisfiedLinkError( 1844 "ClassLoader.findLibrary failed to return an absolute path: " + libfilename); 1845 } 1846 if (loadLibrary0(fromClass, libfile)) { 1847 return; 1848 } 1849 throw new UnsatisfiedLinkError("Can't load " + libfilename); 1850 } 1851 } 1852 for (int i = 0 ; i < sys_paths.length ; i++) { 1853 File libfile = new File(sys_paths[i], System.mapLibraryName(name)); 1854 if (loadLibrary0(fromClass, libfile)) { 1855 return; 1856 } 1857 } 1858 if (loader != null) { 1859 for (int i = 0 ; i < usr_paths.length ; i++) { 1860 File libfile = new File(usr_paths[i], 1861 System.mapLibraryName(name)); 1862 if (loadLibrary0(fromClass, libfile)) { 1863 return; 1864 } 1865 } 1866 } 1867 // Oops, it failed 1868 throw new UnsatisfiedLinkError("no " + name + " in java.library.path"); 1869 } 1870 1871 private static boolean loadLibrary0(Class fromClass, final File file) { 1872 boolean exists = AccessController.doPrivileged( 1873 new PrivilegedAction<Object>() { 1874 public Object run() { 1875 return file.exists() ? Boolean.TRUE : null; 1876 }}) 1877 != null; 1878 if (!exists) { 1879 return false; 1880 } 1881 String name; 1882 try { 1883 name = file.getCanonicalPath(); 1884 } catch (IOException e) { 1885 return false; 1886 } 1887 ClassLoader loader = 1888 (fromClass == null) ? null : fromClass.getClassLoader(); 1889 Vector<NativeLibrary> libs = 1890 loader != null ? loader.nativeLibraries : systemNativeLibraries; 1891 synchronized (libs) { 1892 int size = libs.size(); 1893 for (int i = 0; i < size; i++) { 1894 NativeLibrary lib = libs.elementAt(i); 1895 if (name.equals(lib.name)) { 1896 return true; 1897 } 1898 } 1899 1900 synchronized (loadedLibraryNames) { 1901 if (loadedLibraryNames.contains(name)) { 1902 throw new UnsatisfiedLinkError 1903 ("Native Library " + 1904 name + 1905 " already loaded in another classloader"); 1906 } 1907 /* If the library is being loaded (must be by the same thread, 1908 * because Runtime.load and Runtime.loadLibrary are 1909 * synchronous). The reason is can occur is that the JNI_OnLoad 1910 * function can cause another loadLibrary invocation. 1911 * 1912 * Thus we can use a static stack to hold the list of libraries 1913 * we are loading. 1914 * 1915 * If there is a pending load operation for the library, we 1916 * immediately return success; otherwise, we raise 1917 * UnsatisfiedLinkError. 1918 */ 1919 int n = nativeLibraryContext.size(); 1920 for (int i = 0; i < n; i++) { 1921 NativeLibrary lib = nativeLibraryContext.elementAt(i); 1922 if (name.equals(lib.name)) { 1923 if (loader == lib.fromClass.getClassLoader()) { 1924 return true; 1925 } else { 1926 throw new UnsatisfiedLinkError 1927 ("Native Library " + 1928 name + 1929 " is being loaded in another classloader"); 1930 } 1931 } 1932 } 1933 NativeLibrary lib = new NativeLibrary(fromClass, name); 1934 nativeLibraryContext.push(lib); 1935 try { 1936 lib.load(name); 1937 } finally { 1938 nativeLibraryContext.pop(); 1939 } 1940 if (lib.handle != 0) { 1941 loadedLibraryNames.addElement(name); 1942 libs.addElement(lib); 1943 return true; 1944 } 1945 return false; 1946 } 1947 } 1948 } 1949 1950 // Invoked in the VM class linking code. 1951 static long findNative(ClassLoader loader, String name) { 1952 Vector<NativeLibrary> libs = 1953 loader != null ? loader.nativeLibraries : systemNativeLibraries; 1954 synchronized (libs) { 1955 int size = libs.size(); 1956 for (int i = 0; i < size; i++) { 1957 NativeLibrary lib = libs.elementAt(i); 1958 long entry = lib.find(name); 1959 if (entry != 0) 1960 return entry; 1961 } 1962 } 1963 return 0; 1964 } 1965 1966 1967 // -- Assertion management -- 1968 1969 final Object assertionLock; 1970 1971 // The default toggle for assertion checking. 1972 // @GuardedBy("assertionLock") 1973 private boolean defaultAssertionStatus = false; 1974 1975 // Maps String packageName to Boolean package default assertion status Note 1976 // that the default package is placed under a null map key. If this field 1977 // is null then we are delegating assertion status queries to the VM, i.e., 1978 // none of this ClassLoader's assertion status modification methods have 1979 // been invoked. 1980 // @GuardedBy("assertionLock") 1981 private Map<String, Boolean> packageAssertionStatus = null; 1982 1983 // Maps String fullyQualifiedClassName to Boolean assertionStatus If this 1984 // field is null then we are delegating assertion status queries to the VM, 1985 // i.e., none of this ClassLoader's assertion status modification methods 1986 // have been invoked. 1987 // @GuardedBy("assertionLock") 1988 Map<String, Boolean> classAssertionStatus = null; 1989 1990 /** 1991 * Sets the default assertion status for this class loader. This setting 1992 * determines whether classes loaded by this class loader and initialized 1993 * in the future will have assertions enabled or disabled by default. 1994 * This setting may be overridden on a per-package or per-class basis by 1995 * invoking {@link #setPackageAssertionStatus(String, boolean)} or {@link 1996 * #setClassAssertionStatus(String, boolean)}. </p> 1997 * 1998 * @param enabled 1999 * <tt>true</tt> if classes loaded by this class loader will 2000 * henceforth have assertions enabled by default, <tt>false</tt> 2001 * if they will have assertions disabled by default. 2002 * 2003 * @since 1.4 2004 */ 2005 public void setDefaultAssertionStatus(boolean enabled) { 2006 synchronized (assertionLock) { 2007 if (classAssertionStatus == null) 2008 initializeJavaAssertionMaps(); 2009 2010 defaultAssertionStatus = enabled; 2011 } 2012 } 2013 2014 /** 2015 * Sets the package default assertion status for the named package. The 2016 * package default assertion status determines the assertion status for 2017 * classes initialized in the future that belong to the named package or 2018 * any of its "subpackages". 2019 * 2020 * <p> A subpackage of a package named p is any package whose name begins 2021 * with "<tt>p.</tt>". For example, <tt>javax.swing.text</tt> is a 2022 * subpackage of <tt>javax.swing</tt>, and both <tt>java.util</tt> and 2023 * <tt>java.lang.reflect</tt> are subpackages of <tt>java</tt>. 2024 * 2025 * <p> In the event that multiple package defaults apply to a given class, 2026 * the package default pertaining to the most specific package takes 2027 * precedence over the others. For example, if <tt>javax.lang</tt> and 2028 * <tt>javax.lang.reflect</tt> both have package defaults associated with 2029 * them, the latter package default applies to classes in 2030 * <tt>javax.lang.reflect</tt>. 2031 * 2032 * <p> Package defaults take precedence over the class loader's default 2033 * assertion status, and may be overridden on a per-class basis by invoking 2034 * {@link #setClassAssertionStatus(String, boolean)}. </p> 2035 * 2036 * @param packageName 2037 * The name of the package whose package default assertion status 2038 * is to be set. A <tt>null</tt> value indicates the unnamed 2039 * package that is "current" 2040 * (<a href="http://java.sun.com/docs/books/jls/">Java Language 2041 * Specification</a>, section 7.4.2). 2042 * 2043 * @param enabled 2044 * <tt>true</tt> if classes loaded by this classloader and 2045 * belonging to the named package or any of its subpackages will 2046 * have assertions enabled by default, <tt>false</tt> if they will 2047 * have assertions disabled by default. 2048 * 2049 * @since 1.4 2050 */ 2051 public void setPackageAssertionStatus(String packageName, 2052 boolean enabled) { 2053 synchronized (assertionLock) { 2054 if (packageAssertionStatus == null) 2055 initializeJavaAssertionMaps(); 2056 2057 packageAssertionStatus.put(packageName, enabled); 2058 } 2059 } 2060 2061 /** 2062 * Sets the desired assertion status for the named top-level class in this 2063 * class loader and any nested classes contained therein. This setting 2064 * takes precedence over the class loader's default assertion status, and 2065 * over any applicable per-package default. This method has no effect if 2066 * the named class has already been initialized. (Once a class is 2067 * initialized, its assertion status cannot change.) 2068 * 2069 * <p> If the named class is not a top-level class, this invocation will 2070 * have no effect on the actual assertion status of any class. </p> 2071 * 2072 * @param className 2073 * The fully qualified class name of the top-level class whose 2074 * assertion status is to be set. 2075 * 2076 * @param enabled 2077 * <tt>true</tt> if the named class is to have assertions 2078 * enabled when (and if) it is initialized, <tt>false</tt> if the 2079 * class is to have assertions disabled. 2080 * 2081 * @since 1.4 2082 */ 2083 public void setClassAssertionStatus(String className, boolean enabled) { 2084 synchronized (assertionLock) { 2085 if (classAssertionStatus == null) 2086 initializeJavaAssertionMaps(); 2087 2088 classAssertionStatus.put(className, enabled); 2089 } 2090 } 2091 2092 /** 2093 * Sets the default assertion status for this class loader to 2094 * <tt>false</tt> and discards any package defaults or class assertion 2095 * status settings associated with the class loader. This method is 2096 * provided so that class loaders can be made to ignore any command line or 2097 * persistent assertion status settings and "start with a clean slate." 2098 * </p> 2099 * 2100 * @since 1.4 2101 */ 2102 public void clearAssertionStatus() { 2103 /* 2104 * Whether or not "Java assertion maps" are initialized, set 2105 * them to empty maps, effectively ignoring any present settings. 2106 */ 2107 synchronized (assertionLock) { 2108 classAssertionStatus = new HashMap<>(); 2109 packageAssertionStatus = new HashMap<>(); 2110 defaultAssertionStatus = false; 2111 } 2112 } 2113 2114 /** 2115 * Returns the assertion status that would be assigned to the specified 2116 * class if it were to be initialized at the time this method is invoked. 2117 * If the named class has had its assertion status set, the most recent 2118 * setting will be returned; otherwise, if any package default assertion 2119 * status pertains to this class, the most recent setting for the most 2120 * specific pertinent package default assertion status is returned; 2121 * otherwise, this class loader's default assertion status is returned. 2122 * </p> 2123 * 2124 * @param className 2125 * The fully qualified class name of the class whose desired 2126 * assertion status is being queried. 2127 * 2128 * @return The desired assertion status of the specified class. 2129 * 2130 * @see #setClassAssertionStatus(String, boolean) 2131 * @see #setPackageAssertionStatus(String, boolean) 2132 * @see #setDefaultAssertionStatus(boolean) 2133 * 2134 * @since 1.4 2135 */ 2136 boolean desiredAssertionStatus(String className) { 2137 synchronized (assertionLock) { 2138 // assert classAssertionStatus != null; 2139 // assert packageAssertionStatus != null; 2140 2141 // Check for a class entry 2142 Boolean result = classAssertionStatus.get(className); 2143 if (result != null) 2144 return result.booleanValue(); 2145 2146 // Check for most specific package entry 2147 int dotIndex = className.lastIndexOf("."); 2148 if (dotIndex < 0) { // default package 2149 result = packageAssertionStatus.get(null); 2150 if (result != null) 2151 return result.booleanValue(); 2152 } 2153 while(dotIndex > 0) { 2154 className = className.substring(0, dotIndex); 2155 result = packageAssertionStatus.get(className); 2156 if (result != null) 2157 return result.booleanValue(); 2158 dotIndex = className.lastIndexOf(".", dotIndex-1); 2159 } 2160 2161 // Return the classloader default 2162 return defaultAssertionStatus; 2163 } 2164 } 2165 2166 // Set up the assertions with information provided by the VM. 2167 // Note: Should only be called inside a synchronized block 2168 private void initializeJavaAssertionMaps() { 2169 // assert Thread.holdsLock(assertionLock); 2170 2171 classAssertionStatus = new HashMap<>(); 2172 packageAssertionStatus = new HashMap<>(); 2173 AssertionStatusDirectives directives = retrieveDirectives(); 2174 2175 for(int i = 0; i < directives.classes.length; i++) 2176 classAssertionStatus.put(directives.classes[i], 2177 directives.classEnabled[i]); 2178 2179 for(int i = 0; i < directives.packages.length; i++) 2180 packageAssertionStatus.put(directives.packages[i], 2181 directives.packageEnabled[i]); 2182 2183 defaultAssertionStatus = directives.deflt; 2184 } 2185 2186 // Retrieves the assertion directives from the VM. 2187 private static native AssertionStatusDirectives retrieveDirectives(); 2188 } 2189 2190 2191 class SystemClassLoaderAction 2192 implements PrivilegedExceptionAction<ClassLoader> { 2193 private ClassLoader parent; 2194 2195 SystemClassLoaderAction(ClassLoader parent) { 2196 this.parent = parent; 2197 } 2198 2199 public ClassLoader run() throws Exception { 2200 String cls = System.getProperty("java.system.class.loader"); 2201 if (cls == null) { 2202 return parent; 2203 } 2204 2205 Constructor ctor = Class.forName(cls, true, parent) 2206 .getDeclaredConstructor(new Class[] { ClassLoader.class }); 2207 ClassLoader sys = (ClassLoader) ctor.newInstance( 2208 new Object[] { parent }); 2209 Thread.currentThread().setContextClassLoader(sys); 2210 return sys; 2211 } 2212 }