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.URL; 33 import java.security.AccessController; 34 import java.security.AccessControlContext; 35 import java.security.CodeSource; 36 import java.security.PrivilegedAction; 37 import java.security.PrivilegedActionException; 38 import java.security.PrivilegedExceptionAction; 39 import java.security.ProtectionDomain; 40 import java.security.cert.Certificate; 41 import java.util.Collections; 42 import java.util.Enumeration; 43 import java.util.HashMap; 44 import java.util.HashSet; 45 import java.util.Set; 46 import java.util.Stack; 47 import java.util.Map; 48 import java.util.Vector; 49 import java.util.Hashtable; 50 import java.util.WeakHashMap; 51 import java.util.concurrent.ConcurrentHashMap; 52 import sun.misc.CompoundEnumeration; 53 import sun.misc.Resource; 54 import sun.misc.URLClassPath; 55 import sun.reflect.CallerSensitive; 56 import sun.reflect.Reflection; 57 import sun.reflect.misc.ReflectUtil; 58 import sun.security.util.SecurityConstants; 59 60 /** 61 * A class loader is an object that is responsible for loading classes. The 62 * class <tt>ClassLoader</tt> is an abstract class. Given the <a 63 * href="#name">binary name</a> of a class, a class loader should attempt to 64 * locate or generate data that constitutes a definition for the class. A 65 * typical strategy is to transform the name into a file name and then read a 66 * "class file" of that name from a file system. 67 * 68 * <p> Every {@link Class <tt>Class</tt>} object contains a {@link 69 * Class#getClassLoader() reference} to the <tt>ClassLoader</tt> that defined 70 * it. 71 * 72 * <p> <tt>Class</tt> objects for array classes are not created by class 73 * loaders, but are created automatically as required by the Java runtime. 74 * The class loader for an array class, as returned by {@link 75 * Class#getClassLoader()} is the same as the class loader for its element 76 * type; if the element type is a primitive type, then the array class has no 77 * class loader. 78 * 79 * <p> Applications implement subclasses of <tt>ClassLoader</tt> in order to 80 * extend the manner in which the Java virtual machine dynamically loads 81 * classes. 82 * 83 * <p> Class loaders may typically be used by security managers to indicate 84 * security domains. 85 * 86 * <p> The <tt>ClassLoader</tt> class uses a delegation model to search for 87 * classes and resources. Each instance of <tt>ClassLoader</tt> has an 88 * associated parent class loader. When requested to find a class or 89 * resource, a <tt>ClassLoader</tt> instance will delegate the search for the 90 * class or resource to its parent class loader before attempting to find the 91 * class or resource itself. The virtual machine's built-in class loader, 92 * called the "bootstrap class loader", does not itself have a parent but may 93 * serve as the parent of a <tt>ClassLoader</tt> instance. 94 * 95 * <p> Class loaders that support concurrent loading of classes are known as 96 * <em>parallel capable</em> class loaders and are required to register 97 * themselves at their class initialization time by invoking the 98 * {@link 99 * #registerAsParallelCapable <tt>ClassLoader.registerAsParallelCapable</tt>} 100 * method. Note that the <tt>ClassLoader</tt> class is registered as parallel 101 * capable by default. However, its subclasses still need to register themselves 102 * if they are parallel capable. <br> 103 * In environments in which the delegation model is not strictly 104 * hierarchical, class loaders need to be parallel capable, otherwise class 105 * loading can lead to deadlocks because the loader lock is held for the 106 * duration of the class loading process (see {@link #loadClass 107 * <tt>loadClass</tt>} methods). 108 * 109 * <p> Normally, the Java virtual machine loads classes from the local file 110 * system in a platform-dependent manner. For example, on UNIX systems, the 111 * virtual machine loads classes from the directory defined by the 112 * <tt>CLASSPATH</tt> environment variable. 113 * 114 * <p> However, some classes may not originate from a file; they may originate 115 * from other sources, such as the network, or they could be constructed by an 116 * application. The method {@link #defineClass(String, byte[], int, int) 117 * <tt>defineClass</tt>} converts an array of bytes into an instance of class 118 * <tt>Class</tt>. Instances of this newly defined class can be created using 119 * {@link Class#newInstance <tt>Class.newInstance</tt>}. 120 * 121 * <p> The methods and constructors of objects created by a class loader may 122 * reference other classes. To determine the class(es) referred to, the Java 123 * virtual machine invokes the {@link #loadClass <tt>loadClass</tt>} method of 124 * the class loader that originally created the class. 125 * 126 * <p> For example, an application could create a network class loader to 127 * download class files from a server. Sample code might look like: 128 * 129 * <blockquote><pre> 130 * ClassLoader loader = new NetworkClassLoader(host, port); 131 * Object main = loader.loadClass("Main", true).newInstance(); 132 * . . . 133 * </pre></blockquote> 134 * 135 * <p> The network class loader subclass must define the methods {@link 136 * #findClass <tt>findClass</tt>} and <tt>loadClassData</tt> to load a class 137 * from the network. Once it has downloaded the bytes that make up the class, 138 * it should use the method {@link #defineClass <tt>defineClass</tt>} to 139 * create a class instance. A sample implementation is: 140 * 141 * <blockquote><pre> 142 * class NetworkClassLoader extends ClassLoader { 143 * String host; 144 * int port; 145 * 146 * public Class findClass(String name) { 147 * byte[] b = loadClassData(name); 148 * return defineClass(name, b, 0, b.length); 149 * } 150 * 151 * private byte[] loadClassData(String name) { 152 * // load the class data from the connection 153 * . . . 154 * } 155 * } 156 * </pre></blockquote> 157 * 158 * <h3> <a name="name">Binary names</a> </h3> 159 * 160 * <p> Any class name provided as a {@link String} parameter to methods in 161 * <tt>ClassLoader</tt> must be a binary name as defined by 162 * <cite>The Java™ Language Specification</cite>. 163 * 164 * <p> Examples of valid class names include: 165 * <blockquote><pre> 166 * "java.lang.String" 167 * "javax.swing.JSpinner$DefaultEditor" 168 * "java.security.KeyStore$Builder$FileBuilder$1" 169 * "java.net.URLClassLoader$3$1" 170 * </pre></blockquote> 171 * 172 * {@code Class} objects for array classes are not created by {@code ClassLoader}; 173 * use the {@link Class#forName} method instead. 174 * 175 * @jls 13.1 The Form of a Binary 176 * @see #resolveClass(Class) 177 * @since 1.0 178 */ 179 public abstract class ClassLoader { 180 181 private static native void registerNatives(); 182 static { 183 registerNatives(); 184 } 185 186 // The parent class loader for delegation 187 // Note: VM hardcoded the offset of this field, thus all new fields 188 // must be added *after* it. 189 private final ClassLoader parent; 190 191 /** 192 * Encapsulates the set of parallel capable loader types. 193 */ 194 private static class ParallelLoaders { 195 private ParallelLoaders() {} 196 197 // the set of parallel capable loader types 198 private static final Set<Class<? extends ClassLoader>> loaderTypes = 199 Collections.newSetFromMap(new WeakHashMap<>()); 200 static { 201 synchronized (loaderTypes) { loaderTypes.add(ClassLoader.class); } 202 } 203 204 /** 205 * Registers the given class loader type as parallel capable. 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 ConcurrentHashMap<String, Package> packages 270 = new ConcurrentHashMap<>(); 271 272 private static Void checkCreateClassLoader() { 273 SecurityManager security = System.getSecurityManager(); 274 if (security != null) { 275 security.checkCreateClassLoader(); 276 } 277 return null; 278 } 279 280 private ClassLoader(Void unused, ClassLoader parent) { 281 this.parent = parent; 282 if (ParallelLoaders.isRegistered(this.getClass())) { 283 parallelLockMap = new ConcurrentHashMap<>(); 284 package2certs = new ConcurrentHashMap<>(); 285 domains = Collections.synchronizedSet(new HashSet<>()); 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>}. 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 * <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. 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 if (ReflectUtil.isNonPublicProxyClass(cls)) { 491 for (Class<?> intf: cls.getInterfaces()) { 492 checkPackageAccess(intf, pd); 493 } 494 return; 495 } 496 497 final String name = cls.getName(); 498 final int i = name.lastIndexOf('.'); 499 if (i != -1) { 500 AccessController.doPrivileged(new PrivilegedAction<Void>() { 501 public Void run() { 502 sm.checkPackageAccess(name.substring(0, i)); 503 return null; 504 } 505 }, new AccessControlContext(new ProtectionDomain[] {pd})); 506 } 507 } 508 domains.add(pd); 509 } 510 511 /** 512 * Finds the class with the specified <a href="#name">binary name</a>. 513 * This method should be overridden by class loader implementations that 514 * follow the delegation model for loading classes, and will be invoked by 515 * the {@link #loadClass <tt>loadClass</tt>} method after checking the 516 * parent class loader for the requested class. The default implementation 517 * throws a <tt>ClassNotFoundException</tt>. 518 * 519 * @param name 520 * The <a href="#name">binary name</a> of the class 521 * 522 * @return The resulting <tt>Class</tt> object 523 * 524 * @throws ClassNotFoundException 525 * If the class could not be found 526 * 527 * @since 1.2 528 */ 529 protected Class<?> findClass(String name) throws ClassNotFoundException { 530 throw new ClassNotFoundException(name); 531 } 532 533 /** 534 * Converts an array of bytes into an instance of class <tt>Class</tt>. 535 * Before the <tt>Class</tt> can be used it must be resolved. This method 536 * is deprecated in favor of the version that takes a <a 537 * href="#name">binary name</a> as its first argument, and is more secure. 538 * 539 * @param b 540 * The bytes that make up the class data. The bytes in positions 541 * <tt>off</tt> through <tt>off+len-1</tt> should have the format 542 * of a valid class file as defined by 543 * <cite>The Java™ Virtual Machine Specification</cite>. 544 * 545 * @param off 546 * The start offset in <tt>b</tt> of the class data 547 * 548 * @param len 549 * The length of the class data 550 * 551 * @return The <tt>Class</tt> object that was created from the specified 552 * class data 553 * 554 * @throws ClassFormatError 555 * If the data did not contain a valid class 556 * 557 * @throws IndexOutOfBoundsException 558 * If either <tt>off</tt> or <tt>len</tt> is negative, or if 559 * <tt>off+len</tt> is greater than <tt>b.length</tt>. 560 * 561 * @throws SecurityException 562 * If an attempt is made to add this class to a package that 563 * contains classes that were signed by a different set of 564 * certificates than this class, or if an attempt is made 565 * to define a class in a package with a fully-qualified name 566 * that starts with "{@code java.}". 567 * 568 * @see #loadClass(String, boolean) 569 * @see #resolveClass(Class) 570 * 571 * @deprecated Replaced by {@link #defineClass(String, byte[], int, int) 572 * defineClass(String, byte[], int, int)} 573 */ 574 @Deprecated 575 protected final Class<?> defineClass(byte[] b, int off, int len) 576 throws ClassFormatError 577 { 578 return defineClass(null, b, off, len, null); 579 } 580 581 /** 582 * Converts an array of bytes into an instance of class <tt>Class</tt>. 583 * Before the <tt>Class</tt> can be used it must be resolved. 584 * 585 * <p> This method assigns a default {@link java.security.ProtectionDomain 586 * <tt>ProtectionDomain</tt>} to the newly defined class. The 587 * <tt>ProtectionDomain</tt> is effectively granted the same set of 588 * permissions returned when {@link 589 * java.security.Policy#getPermissions(java.security.CodeSource) 590 * <tt>Policy.getPolicy().getPermissions(new CodeSource(null, null))</tt>} 591 * is invoked. The default domain is created on the first invocation of 592 * {@link #defineClass(String, byte[], int, int) <tt>defineClass</tt>}, 593 * and re-used on subsequent invocations. 594 * 595 * <p> To assign a specific <tt>ProtectionDomain</tt> to the class, use 596 * the {@link #defineClass(String, byte[], int, int, 597 * java.security.ProtectionDomain) <tt>defineClass</tt>} method that takes a 598 * <tt>ProtectionDomain</tt> as one of its arguments. </p> 599 * 600 * @param name 601 * The expected <a href="#name">binary name</a> of the class, or 602 * <tt>null</tt> if not known 603 * 604 * @param b 605 * The bytes that make up the class data. The bytes in positions 606 * <tt>off</tt> through <tt>off+len-1</tt> should have the format 607 * of a valid class file as defined by 608 * <cite>The Java™ Virtual Machine Specification</cite>. 609 * 610 * @param off 611 * The start offset in <tt>b</tt> of the class data 612 * 613 * @param len 614 * The length of the class data 615 * 616 * @return The <tt>Class</tt> object that was created from the specified 617 * class data. 618 * 619 * @throws ClassFormatError 620 * If the data did not contain a valid class 621 * 622 * @throws IndexOutOfBoundsException 623 * If either <tt>off</tt> or <tt>len</tt> is negative, or if 624 * <tt>off+len</tt> is greater than <tt>b.length</tt>. 625 * 626 * @throws SecurityException 627 * If an attempt is made to add this class to a package that 628 * contains classes that were signed by a different set of 629 * certificates than this class (which is unsigned), or if 630 * <tt>name</tt> begins with "<tt>java.</tt>". 631 * 632 * @see #loadClass(String, boolean) 633 * @see #resolveClass(Class) 634 * @see java.security.CodeSource 635 * @see java.security.SecureClassLoader 636 * 637 * @since 1.1 638 */ 639 protected final Class<?> defineClass(String name, byte[] b, int off, int len) 640 throws ClassFormatError 641 { 642 return defineClass(name, b, off, len, null); 643 } 644 645 /* Determine protection domain, and check that: 646 - not define java.* class, 647 - signer of this class matches signers for the rest of the classes in 648 package. 649 */ 650 private ProtectionDomain preDefineClass(String name, 651 ProtectionDomain pd) 652 { 653 if (!checkName(name)) 654 throw new NoClassDefFoundError("IllegalName: " + name); 655 656 if ((name != null) && name.startsWith("java.")) { 657 throw new SecurityException 658 ("Prohibited package name: " + 659 name.substring(0, name.lastIndexOf('.'))); 660 } 661 if (pd == null) { 662 pd = defaultDomain; 663 } 664 665 if (name != null) checkCerts(name, pd.getCodeSource()); 666 667 return pd; 668 } 669 670 private String defineClassSourceLocation(ProtectionDomain pd) 671 { 672 CodeSource cs = pd.getCodeSource(); 673 String source = null; 674 if (cs != null && cs.getLocation() != null) { 675 source = cs.getLocation().toString(); 676 } 677 return source; 678 } 679 680 private void postDefineClass(Class<?> c, ProtectionDomain pd) 681 { 682 if (pd.getCodeSource() != null) { 683 Certificate certs[] = pd.getCodeSource().getCertificates(); 684 if (certs != null) 685 setSigners(c, certs); 686 } 687 } 688 689 /** 690 * Converts an array of bytes into an instance of class <tt>Class</tt>, 691 * with an optional <tt>ProtectionDomain</tt>. If the domain is 692 * <tt>null</tt>, then a default domain will be assigned to the class as 693 * specified in the documentation for {@link #defineClass(String, byte[], 694 * int, int)}. Before the class can be used it must be resolved. 695 * 696 * <p> The first class defined in a package determines the exact set of 697 * certificates that all subsequent classes defined in that package must 698 * contain. The set of certificates for a class is obtained from the 699 * {@link java.security.CodeSource <tt>CodeSource</tt>} within the 700 * <tt>ProtectionDomain</tt> of the class. Any classes added to that 701 * package must contain the same set of certificates or a 702 * <tt>SecurityException</tt> will be thrown. Note that if 703 * <tt>name</tt> is <tt>null</tt>, this check is not performed. 704 * You should always pass in the <a href="#name">binary name</a> of the 705 * class you are defining as well as the bytes. This ensures that the 706 * class you are defining is indeed the class you think it is. 707 * 708 * <p> The specified <tt>name</tt> cannot begin with "<tt>java.</tt>", since 709 * all classes in the "<tt>java.*</tt> packages can only be defined by the 710 * bootstrap class loader. If <tt>name</tt> is not <tt>null</tt>, it 711 * must be equal to the <a href="#name">binary name</a> of the class 712 * specified by the byte array "<tt>b</tt>", otherwise a {@link 713 * NoClassDefFoundError <tt>NoClassDefFoundError</tt>} will be thrown. </p> 714 * 715 * @param name 716 * The expected <a href="#name">binary name</a> of the class, or 717 * <tt>null</tt> if not known 718 * 719 * @param b 720 * The bytes that make up the class data. The bytes in positions 721 * <tt>off</tt> through <tt>off+len-1</tt> should have the format 722 * of a valid class file as defined by 723 * <cite>The Java™ Virtual Machine Specification</cite>. 724 * 725 * @param off 726 * The start offset in <tt>b</tt> of the class data 727 * 728 * @param len 729 * The length of the class data 730 * 731 * @param protectionDomain 732 * The ProtectionDomain of the class 733 * 734 * @return The <tt>Class</tt> object created from the data, 735 * and optional <tt>ProtectionDomain</tt>. 736 * 737 * @throws ClassFormatError 738 * If the data did not contain a valid class 739 * 740 * @throws NoClassDefFoundError 741 * If <tt>name</tt> is not equal to the <a href="#name">binary 742 * name</a> of the class specified by <tt>b</tt> 743 * 744 * @throws IndexOutOfBoundsException 745 * If either <tt>off</tt> or <tt>len</tt> is negative, or if 746 * <tt>off+len</tt> is greater than <tt>b.length</tt>. 747 * 748 * @throws SecurityException 749 * If an attempt is made to add this class to a package that 750 * contains classes that were signed by a different set of 751 * certificates than this class, or if <tt>name</tt> begins with 752 * "<tt>java.</tt>". 753 */ 754 protected final Class<?> defineClass(String name, byte[] b, int off, int len, 755 ProtectionDomain protectionDomain) 756 throws ClassFormatError 757 { 758 protectionDomain = preDefineClass(name, protectionDomain); 759 String source = defineClassSourceLocation(protectionDomain); 760 Class<?> c = defineClass1(name, b, off, len, protectionDomain, source); 761 postDefineClass(c, protectionDomain); 762 return c; 763 } 764 765 /** 766 * Converts a {@link java.nio.ByteBuffer <tt>ByteBuffer</tt>} 767 * into an instance of class <tt>Class</tt>, 768 * with an optional <tt>ProtectionDomain</tt>. If the domain is 769 * <tt>null</tt>, then a default domain will be assigned to the class as 770 * specified in the documentation for {@link #defineClass(String, byte[], 771 * int, int)}. Before the class can be used it must be resolved. 772 * 773 * <p>The rules about the first class defined in a package determining the 774 * set of certificates for the package, and the restrictions on class names 775 * are identical to those specified in the documentation for {@link 776 * #defineClass(String, byte[], int, int, ProtectionDomain)}. 777 * 778 * <p> An invocation of this method of the form 779 * <i>cl</i><tt>.defineClass(</tt><i>name</i><tt>,</tt> 780 * <i>bBuffer</i><tt>,</tt> <i>pd</i><tt>)</tt> yields exactly the same 781 * result as the statements 782 * 783 *<p> <tt> 784 * ...<br> 785 * byte[] temp = new byte[bBuffer.{@link 786 * java.nio.ByteBuffer#remaining remaining}()];<br> 787 * bBuffer.{@link java.nio.ByteBuffer#get(byte[]) 788 * get}(temp);<br> 789 * return {@link #defineClass(String, byte[], int, int, ProtectionDomain) 790 * cl.defineClass}(name, temp, 0, 791 * temp.length, pd);<br> 792 * </tt></p> 793 * 794 * @param name 795 * The expected <a href="#name">binary name</a>. of the class, or 796 * <tt>null</tt> if not known 797 * 798 * @param b 799 * The bytes that make up the class data. The bytes from positions 800 * <tt>b.position()</tt> through <tt>b.position() + b.limit() -1 801 * </tt> should have the format of a valid class file as defined by 802 * <cite>The Java™ Virtual Machine Specification</cite>. 803 * 804 * @param protectionDomain 805 * The ProtectionDomain of the class, or <tt>null</tt>. 806 * 807 * @return The <tt>Class</tt> object created from the data, 808 * and optional <tt>ProtectionDomain</tt>. 809 * 810 * @throws ClassFormatError 811 * If the data did not contain a valid class. 812 * 813 * @throws NoClassDefFoundError 814 * If <tt>name</tt> is not equal to the <a href="#name">binary 815 * name</a> of the class specified by <tt>b</tt> 816 * 817 * @throws SecurityException 818 * If an attempt is made to add this class to a package that 819 * contains classes that were signed by a different set of 820 * certificates than this class, or if <tt>name</tt> begins with 821 * "<tt>java.</tt>". 822 * 823 * @see #defineClass(String, byte[], int, int, ProtectionDomain) 824 * 825 * @since 1.5 826 */ 827 protected final Class<?> defineClass(String name, java.nio.ByteBuffer b, 828 ProtectionDomain protectionDomain) 829 throws ClassFormatError 830 { 831 int len = b.remaining(); 832 833 // Use byte[] if not a direct ByteBuffer: 834 if (!b.isDirect()) { 835 if (b.hasArray()) { 836 return defineClass(name, b.array(), 837 b.position() + b.arrayOffset(), len, 838 protectionDomain); 839 } else { 840 // no array, or read-only array 841 byte[] tb = new byte[len]; 842 b.get(tb); // get bytes out of byte buffer. 843 return defineClass(name, tb, 0, len, protectionDomain); 844 } 845 } 846 847 protectionDomain = preDefineClass(name, protectionDomain); 848 String source = defineClassSourceLocation(protectionDomain); 849 Class<?> c = defineClass2(name, b, b.position(), len, protectionDomain, source); 850 postDefineClass(c, protectionDomain); 851 return c; 852 } 853 854 private native Class<?> defineClass1(String name, byte[] b, int off, int len, 855 ProtectionDomain pd, String source); 856 857 private native Class<?> defineClass2(String name, java.nio.ByteBuffer b, 858 int off, int len, ProtectionDomain pd, 859 String source); 860 861 // true if the name is null or has the potential to be a valid binary name 862 private boolean checkName(String name) { 863 if ((name == null) || (name.length() == 0)) 864 return true; 865 if ((name.indexOf('/') != -1) || (name.charAt(0) == '[')) 866 return false; 867 return true; 868 } 869 870 private void checkCerts(String name, CodeSource cs) { 871 int i = name.lastIndexOf('.'); 872 String pname = (i == -1) ? "" : name.substring(0, i); 873 874 Certificate[] certs = null; 875 if (cs != null) { 876 certs = cs.getCertificates(); 877 } 878 Certificate[] pcerts = null; 879 if (parallelLockMap == null) { 880 synchronized (this) { 881 pcerts = package2certs.get(pname); 882 if (pcerts == null) { 883 package2certs.put(pname, (certs == null? nocerts:certs)); 884 } 885 } 886 } else { 887 pcerts = ((ConcurrentHashMap<String, Certificate[]>)package2certs). 888 putIfAbsent(pname, (certs == null? nocerts:certs)); 889 } 890 if (pcerts != null && !compareCerts(pcerts, certs)) { 891 throw new SecurityException("class \""+ name + 892 "\"'s signer information does not match signer information of other classes in the same package"); 893 } 894 } 895 896 /** 897 * check to make sure the certs for the new class (certs) are the same as 898 * the certs for the first class inserted in the package (pcerts) 899 */ 900 private boolean compareCerts(Certificate[] pcerts, 901 Certificate[] certs) 902 { 903 // certs can be null, indicating no certs. 904 if ((certs == null) || (certs.length == 0)) { 905 return pcerts.length == 0; 906 } 907 908 // the length must be the same at this point 909 if (certs.length != pcerts.length) 910 return false; 911 912 // go through and make sure all the certs in one array 913 // are in the other and vice-versa. 914 boolean match; 915 for (Certificate cert : certs) { 916 match = false; 917 for (Certificate pcert : pcerts) { 918 if (cert.equals(pcert)) { 919 match = true; 920 break; 921 } 922 } 923 if (!match) return false; 924 } 925 926 // now do the same for pcerts 927 for (Certificate pcert : pcerts) { 928 match = false; 929 for (Certificate cert : certs) { 930 if (pcert.equals(cert)) { 931 match = true; 932 break; 933 } 934 } 935 if (!match) return false; 936 } 937 938 return true; 939 } 940 941 /** 942 * Links the specified class. This (misleadingly named) method may be 943 * used by a class loader to link a class. If the class <tt>c</tt> has 944 * already been linked, then this method simply returns. Otherwise, the 945 * class is linked as described in the "Execution" chapter of 946 * <cite>The Java™ Language Specification</cite>. 947 * 948 * @param c 949 * The class to link 950 * 951 * @throws NullPointerException 952 * If <tt>c</tt> is <tt>null</tt>. 953 * 954 * @see #defineClass(String, byte[], int, int) 955 */ 956 protected final void resolveClass(Class<?> c) { 957 resolveClass0(c); 958 } 959 960 private native void resolveClass0(Class<?> c); 961 962 /** 963 * Finds a class with the specified <a href="#name">binary name</a>, 964 * loading it if necessary. 965 * 966 * <p> This method loads the class through the system class loader (see 967 * {@link #getSystemClassLoader()}). The <tt>Class</tt> object returned 968 * might have more than one <tt>ClassLoader</tt> associated with it. 969 * Subclasses of <tt>ClassLoader</tt> need not usually invoke this method, 970 * because most class loaders need to override just {@link 971 * #findClass(String)}. </p> 972 * 973 * @param name 974 * The <a href="#name">binary name</a> of the class 975 * 976 * @return The <tt>Class</tt> object for the specified <tt>name</tt> 977 * 978 * @throws ClassNotFoundException 979 * If the class could not be found 980 * 981 * @see #ClassLoader(ClassLoader) 982 * @see #getParent() 983 */ 984 protected final Class<?> findSystemClass(String name) 985 throws ClassNotFoundException 986 { 987 ClassLoader system = getSystemClassLoader(); 988 if (system == null) { 989 if (!checkName(name)) 990 throw new ClassNotFoundException(name); 991 Class<?> cls = findBootstrapClass(name); 992 if (cls == null) { 993 throw new ClassNotFoundException(name); 994 } 995 return cls; 996 } 997 return system.loadClass(name); 998 } 999 1000 /** 1001 * Returns a class loaded by the bootstrap class loader; 1002 * or return null if not found. 1003 */ 1004 private Class<?> findBootstrapClassOrNull(String name) 1005 { 1006 if (!checkName(name)) return null; 1007 1008 return findBootstrapClass(name); 1009 } 1010 1011 // return null if not found 1012 private native Class<?> findBootstrapClass(String name); 1013 1014 /** 1015 * Returns the class with the given <a href="#name">binary name</a> if this 1016 * loader has been recorded by the Java virtual machine as an initiating 1017 * loader of a class with that <a href="#name">binary name</a>. Otherwise 1018 * <tt>null</tt> is returned. 1019 * 1020 * @param name 1021 * The <a href="#name">binary name</a> of the class 1022 * 1023 * @return The <tt>Class</tt> object, or <tt>null</tt> if the class has 1024 * not been loaded 1025 * 1026 * @since 1.1 1027 */ 1028 protected final Class<?> findLoadedClass(String name) { 1029 if (!checkName(name)) 1030 return null; 1031 return findLoadedClass0(name); 1032 } 1033 1034 private native final Class<?> findLoadedClass0(String name); 1035 1036 /** 1037 * Sets the signers of a class. This should be invoked after defining a 1038 * class. 1039 * 1040 * @param c 1041 * The <tt>Class</tt> object 1042 * 1043 * @param signers 1044 * The signers for the class 1045 * 1046 * @since 1.1 1047 */ 1048 protected final void setSigners(Class<?> c, Object[] signers) { 1049 c.setSigners(signers); 1050 } 1051 1052 1053 // -- Resource -- 1054 1055 /** 1056 * Finds the resource with the given name. A resource is some data 1057 * (images, audio, text, etc) that can be accessed by class code in a way 1058 * that is independent of the location of the code. 1059 * 1060 * <p> The name of a resource is a '<tt>/</tt>'-separated path name that 1061 * identifies the resource. 1062 * 1063 * <p> This method will first search the parent class loader for the 1064 * resource; if the parent is <tt>null</tt> the path of the class loader 1065 * built-in to the virtual machine is searched. That failing, this method 1066 * will invoke {@link #findResource(String)} to find the resource. </p> 1067 * 1068 * @apiNote When overriding this method it is recommended that an 1069 * implementation ensures that any delegation is consistent with the {@link 1070 * #getResources(java.lang.String) getResources(String)} method. 1071 * 1072 * @param name 1073 * The resource name 1074 * 1075 * @return A <tt>URL</tt> object for reading the resource, or 1076 * <tt>null</tt> if the resource could not be found or the invoker 1077 * doesn't have adequate privileges to get the resource. 1078 * 1079 * @since 1.1 1080 */ 1081 public URL getResource(String name) { 1082 URL url; 1083 if (parent != null) { 1084 url = parent.getResource(name); 1085 } else { 1086 url = getBootstrapResource(name); 1087 } 1088 if (url == null) { 1089 url = findResource(name); 1090 } 1091 return url; 1092 } 1093 1094 /** 1095 * Finds all the resources with the given name. A resource is some data 1096 * (images, audio, text, etc) that can be accessed by class code in a way 1097 * that is independent of the location of the code. 1098 * 1099 * <p>The name of a resource is a <tt>/</tt>-separated path name that 1100 * identifies the resource. 1101 * 1102 * <p> The search order is described in the documentation for {@link 1103 * #getResource(String)}. </p> 1104 * 1105 * @apiNote When overriding this method it is recommended that an 1106 * implementation ensures that any delegation is consistent with the {@link 1107 * #getResource(java.lang.String) getResource(String)} method. This should 1108 * ensure that the first element returned by the Enumeration's 1109 * {@code nextElement} method is the same resource that the 1110 * {@code getResource(String)} method would return. 1111 * 1112 * @param name 1113 * The resource name 1114 * 1115 * @return An enumeration of {@link java.net.URL <tt>URL</tt>} objects for 1116 * the resource. If no resources could be found, the enumeration 1117 * will be empty. Resources that the class loader doesn't have 1118 * access to will not be in the enumeration. 1119 * 1120 * @throws IOException 1121 * If I/O errors occur 1122 * 1123 * @see #findResources(String) 1124 * 1125 * @since 1.2 1126 */ 1127 public Enumeration<URL> getResources(String name) throws IOException { 1128 @SuppressWarnings("unchecked") 1129 Enumeration<URL>[] tmp = (Enumeration<URL>[]) new Enumeration<?>[2]; 1130 if (parent != null) { 1131 tmp[0] = parent.getResources(name); 1132 } else { 1133 tmp[0] = getBootstrapResources(name); 1134 } 1135 tmp[1] = findResources(name); 1136 1137 return new CompoundEnumeration<>(tmp); 1138 } 1139 1140 /** 1141 * Finds the resource with the given name. Class loader implementations 1142 * should override this method to specify where to find resources. 1143 * 1144 * @param name 1145 * The resource name 1146 * 1147 * @return A <tt>URL</tt> object for reading the resource, or 1148 * <tt>null</tt> if the resource could not be found 1149 * 1150 * @since 1.2 1151 */ 1152 protected URL findResource(String name) { 1153 return null; 1154 } 1155 1156 /** 1157 * Returns an enumeration of {@link java.net.URL <tt>URL</tt>} objects 1158 * representing all the resources with the given name. Class loader 1159 * implementations should override this method to specify where to load 1160 * resources from. 1161 * 1162 * @param name 1163 * The resource name 1164 * 1165 * @return An enumeration of {@link java.net.URL <tt>URL</tt>} objects for 1166 * the resources 1167 * 1168 * @throws IOException 1169 * If I/O errors occur 1170 * 1171 * @since 1.2 1172 */ 1173 protected Enumeration<URL> findResources(String name) throws IOException { 1174 return java.util.Collections.emptyEnumeration(); 1175 } 1176 1177 /** 1178 * Registers the caller as parallel capable. 1179 * The registration succeeds if and only if all of the following 1180 * conditions are met: 1181 * <ol> 1182 * <li> no instance of the caller has been created</li> 1183 * <li> all of the super classes (except class Object) of the caller are 1184 * registered as parallel capable</li> 1185 * </ol> 1186 * <p>Note that once a class loader is registered as parallel capable, there 1187 * is no way to change it back.</p> 1188 * 1189 * @return true if the caller is successfully registered as 1190 * parallel capable and false if otherwise. 1191 * 1192 * @since 1.7 1193 */ 1194 @CallerSensitive 1195 protected static boolean registerAsParallelCapable() { 1196 Class<? extends ClassLoader> callerClass = 1197 Reflection.getCallerClass().asSubclass(ClassLoader.class); 1198 return ParallelLoaders.register(callerClass); 1199 } 1200 1201 /** 1202 * Find a resource of the specified name from the search path used to load 1203 * classes. This method locates the resource through the system class 1204 * loader (see {@link #getSystemClassLoader()}). 1205 * 1206 * @param name 1207 * The resource name 1208 * 1209 * @return A {@link java.net.URL <tt>URL</tt>} object for reading the 1210 * resource, or <tt>null</tt> if the resource could not be found 1211 * 1212 * @since 1.1 1213 */ 1214 public static URL getSystemResource(String name) { 1215 ClassLoader system = getSystemClassLoader(); 1216 if (system == null) { 1217 return getBootstrapResource(name); 1218 } 1219 return system.getResource(name); 1220 } 1221 1222 /** 1223 * Finds all resources of the specified name from the search path used to 1224 * load classes. The resources thus found are returned as an 1225 * {@link java.util.Enumeration <tt>Enumeration</tt>} of {@link 1226 * java.net.URL <tt>URL</tt>} objects. 1227 * 1228 * <p> The search order is described in the documentation for {@link 1229 * #getSystemResource(String)}. </p> 1230 * 1231 * @param name 1232 * The resource name 1233 * 1234 * @return An enumeration of resource {@link java.net.URL <tt>URL</tt>} 1235 * objects 1236 * 1237 * @throws IOException 1238 * If I/O errors occur 1239 1240 * @since 1.2 1241 */ 1242 public static Enumeration<URL> getSystemResources(String name) 1243 throws IOException 1244 { 1245 ClassLoader system = getSystemClassLoader(); 1246 if (system == null) { 1247 return getBootstrapResources(name); 1248 } 1249 return system.getResources(name); 1250 } 1251 1252 /** 1253 * Find resources from the VM's built-in classloader. 1254 */ 1255 private static URL getBootstrapResource(String name) { 1256 URLClassPath ucp = getBootstrapClassPath(); 1257 Resource res = ucp.getResource(name); 1258 return res != null ? res.getURL() : null; 1259 } 1260 1261 /** 1262 * Find resources from the VM's built-in classloader. 1263 */ 1264 private static Enumeration<URL> getBootstrapResources(String name) 1265 throws IOException 1266 { 1267 final Enumeration<Resource> e = 1268 getBootstrapClassPath().getResources(name); 1269 return new Enumeration<URL> () { 1270 public URL nextElement() { 1271 return e.nextElement().getURL(); 1272 } 1273 public boolean hasMoreElements() { 1274 return e.hasMoreElements(); 1275 } 1276 }; 1277 } 1278 1279 // Returns the URLClassPath that is used for finding system resources. 1280 static URLClassPath getBootstrapClassPath() { 1281 return sun.misc.Launcher.getBootstrapClassPath(); 1282 } 1283 1284 1285 /** 1286 * Returns an input stream for reading the specified resource. 1287 * 1288 * <p> The search order is described in the documentation for {@link 1289 * #getResource(String)}. </p> 1290 * 1291 * @param name 1292 * The resource name 1293 * 1294 * @return An input stream for reading the resource, or <tt>null</tt> 1295 * if the resource could not be found 1296 * 1297 * @since 1.1 1298 */ 1299 public InputStream getResourceAsStream(String name) { 1300 URL url = getResource(name); 1301 try { 1302 return url != null ? url.openStream() : null; 1303 } catch (IOException e) { 1304 return null; 1305 } 1306 } 1307 1308 /** 1309 * Open for reading, a resource of the specified name from the search path 1310 * used to load classes. This method locates the resource through the 1311 * system class loader (see {@link #getSystemClassLoader()}). 1312 * 1313 * @param name 1314 * The resource name 1315 * 1316 * @return An input stream for reading the resource, or <tt>null</tt> 1317 * if the resource could not be found 1318 * 1319 * @since 1.1 1320 */ 1321 public static InputStream getSystemResourceAsStream(String name) { 1322 URL url = getSystemResource(name); 1323 try { 1324 return url != null ? url.openStream() : null; 1325 } catch (IOException e) { 1326 return null; 1327 } 1328 } 1329 1330 1331 // -- Hierarchy -- 1332 1333 /** 1334 * Returns the parent class loader for delegation. Some implementations may 1335 * use <tt>null</tt> to represent the bootstrap class loader. This method 1336 * will return <tt>null</tt> in such implementations if this class loader's 1337 * parent is the bootstrap class loader. 1338 * 1339 * <p> If a security manager is present, and the invoker's class loader is 1340 * not <tt>null</tt> and is not an ancestor of this class loader, then this 1341 * method invokes the security manager's {@link 1342 * SecurityManager#checkPermission(java.security.Permission) 1343 * <tt>checkPermission</tt>} method with a {@link 1344 * RuntimePermission#RuntimePermission(String) 1345 * <tt>RuntimePermission("getClassLoader")</tt>} permission to verify 1346 * access to the parent class loader is permitted. If not, a 1347 * <tt>SecurityException</tt> will be thrown. </p> 1348 * 1349 * @return The parent <tt>ClassLoader</tt> 1350 * 1351 * @throws SecurityException 1352 * If a security manager exists and its <tt>checkPermission</tt> 1353 * method doesn't allow access to this class loader's parent class 1354 * loader. 1355 * 1356 * @since 1.2 1357 */ 1358 @CallerSensitive 1359 public final ClassLoader getParent() { 1360 if (parent == null) 1361 return null; 1362 SecurityManager sm = System.getSecurityManager(); 1363 if (sm != null) { 1364 checkClassLoaderPermission(this, Reflection.getCallerClass()); 1365 } 1366 return parent; 1367 } 1368 1369 /** 1370 * Returns the system class loader for delegation. This is the default 1371 * delegation parent for new <tt>ClassLoader</tt> instances, and is 1372 * typically the class loader used to start the application. 1373 * 1374 * <p> This method is first invoked early in the runtime's startup 1375 * sequence, at which point it creates the system class loader and sets it 1376 * as the context class loader of the invoking <tt>Thread</tt>. 1377 * 1378 * <p> The default system class loader is an implementation-dependent 1379 * instance of this class. 1380 * 1381 * <p> If the system property "<tt>java.system.class.loader</tt>" is defined 1382 * when this method is first invoked then the value of that property is 1383 * taken to be the name of a class that will be returned as the system 1384 * class loader. The class is loaded using the default system class loader 1385 * and must define a public constructor that takes a single parameter of 1386 * type <tt>ClassLoader</tt> which is used as the delegation parent. An 1387 * instance is then created using this constructor with the default system 1388 * class loader as the parameter. The resulting class loader is defined 1389 * to be the system class loader. 1390 * 1391 * <p> If a security manager is present, and the invoker's class loader is 1392 * not <tt>null</tt> and the invoker's class loader is not the same as or 1393 * an ancestor of the system class loader, then this method invokes the 1394 * security manager's {@link 1395 * SecurityManager#checkPermission(java.security.Permission) 1396 * <tt>checkPermission</tt>} method with a {@link 1397 * RuntimePermission#RuntimePermission(String) 1398 * <tt>RuntimePermission("getClassLoader")</tt>} permission to verify 1399 * access to the system class loader. If not, a 1400 * <tt>SecurityException</tt> will be thrown. </p> 1401 * 1402 * @return The system <tt>ClassLoader</tt> for delegation, or 1403 * <tt>null</tt> if none 1404 * 1405 * @throws SecurityException 1406 * If a security manager exists and its <tt>checkPermission</tt> 1407 * method doesn't allow access to the system class loader. 1408 * 1409 * @throws IllegalStateException 1410 * If invoked recursively during the construction of the class 1411 * loader specified by the "<tt>java.system.class.loader</tt>" 1412 * property. 1413 * 1414 * @throws Error 1415 * If the system property "<tt>java.system.class.loader</tt>" 1416 * is defined but the named class could not be loaded, the 1417 * provider class does not define the required constructor, or an 1418 * exception is thrown by that constructor when it is invoked. The 1419 * underlying cause of the error can be retrieved via the 1420 * {@link Throwable#getCause()} method. 1421 * 1422 * @revised 1.4 1423 */ 1424 @CallerSensitive 1425 public static ClassLoader getSystemClassLoader() { 1426 initSystemClassLoader(); 1427 if (scl == null) { 1428 return null; 1429 } 1430 SecurityManager sm = System.getSecurityManager(); 1431 if (sm != null) { 1432 checkClassLoaderPermission(scl, Reflection.getCallerClass()); 1433 } 1434 return scl; 1435 } 1436 1437 private static synchronized void initSystemClassLoader() { 1438 if (!sclSet) { 1439 if (scl != null) 1440 throw new IllegalStateException("recursive invocation"); 1441 sun.misc.Launcher l = sun.misc.Launcher.getLauncher(); 1442 if (l != null) { 1443 Throwable oops = null; 1444 scl = l.getClassLoader(); 1445 try { 1446 scl = AccessController.doPrivileged( 1447 new SystemClassLoaderAction(scl)); 1448 } catch (PrivilegedActionException pae) { 1449 oops = pae.getCause(); 1450 if (oops instanceof InvocationTargetException) { 1451 oops = oops.getCause(); 1452 } 1453 } 1454 if (oops != null) { 1455 if (oops instanceof Error) { 1456 throw (Error) oops; 1457 } else { 1458 // wrap the exception 1459 throw new Error(oops); 1460 } 1461 } 1462 } 1463 sclSet = true; 1464 } 1465 } 1466 1467 // Returns true if the specified class loader can be found in this class 1468 // loader's delegation chain. 1469 boolean isAncestor(ClassLoader cl) { 1470 ClassLoader acl = this; 1471 do { 1472 acl = acl.parent; 1473 if (cl == acl) { 1474 return true; 1475 } 1476 } while (acl != null); 1477 return false; 1478 } 1479 1480 // Tests if class loader access requires "getClassLoader" permission 1481 // check. A class loader 'from' can access class loader 'to' if 1482 // class loader 'from' is same as class loader 'to' or an ancestor 1483 // of 'to'. The class loader in a system domain can access 1484 // any class loader. 1485 private static boolean needsClassLoaderPermissionCheck(ClassLoader from, 1486 ClassLoader to) 1487 { 1488 if (from == to) 1489 return false; 1490 1491 if (from == null) 1492 return false; 1493 1494 return !to.isAncestor(from); 1495 } 1496 1497 // Returns the class's class loader, or null if none. 1498 static ClassLoader getClassLoader(Class<?> caller) { 1499 // This can be null if the VM is requesting it 1500 if (caller == null) { 1501 return null; 1502 } 1503 // Circumvent security check since this is package-private 1504 return caller.getClassLoader0(); 1505 } 1506 1507 static void checkClassLoaderPermission(ClassLoader cl, Class<?> caller) { 1508 SecurityManager sm = System.getSecurityManager(); 1509 if (sm != null) { 1510 // caller can be null if the VM is requesting it 1511 ClassLoader ccl = getClassLoader(caller); 1512 if (needsClassLoaderPermissionCheck(ccl, cl)) { 1513 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION); 1514 } 1515 } 1516 } 1517 1518 // The class loader for the system 1519 // @GuardedBy("ClassLoader.class") 1520 private static ClassLoader scl; 1521 1522 // Set to true once the system class loader has been set 1523 // @GuardedBy("ClassLoader.class") 1524 private static boolean sclSet; 1525 1526 1527 // -- Package -- 1528 1529 /** 1530 * Defines a package by name in this <tt>ClassLoader</tt>. This allows 1531 * class loaders to define the packages for their classes. Packages must 1532 * be created before the class is defined, and package names must be 1533 * unique within a class loader and cannot be redefined or changed once 1534 * created. 1535 * 1536 * @param name 1537 * The package name 1538 * 1539 * @param specTitle 1540 * The specification title 1541 * 1542 * @param specVersion 1543 * The specification version 1544 * 1545 * @param specVendor 1546 * The specification vendor 1547 * 1548 * @param implTitle 1549 * The implementation title 1550 * 1551 * @param implVersion 1552 * The implementation version 1553 * 1554 * @param implVendor 1555 * The implementation vendor 1556 * 1557 * @param sealBase 1558 * If not <tt>null</tt>, then this package is sealed with 1559 * respect to the given code source {@link java.net.URL 1560 * <tt>URL</tt>} object. Otherwise, the package is not sealed. 1561 * 1562 * @return The newly defined <tt>Package</tt> object 1563 * 1564 * @throws IllegalArgumentException 1565 * If package name duplicates an existing package either in this 1566 * class loader or one of its ancestors 1567 * 1568 * @since 1.2 1569 */ 1570 protected Package definePackage(String name, String specTitle, 1571 String specVersion, String specVendor, 1572 String implTitle, String implVersion, 1573 String implVendor, URL sealBase) 1574 throws IllegalArgumentException 1575 { 1576 Package pkg = getPackage(name); 1577 if (pkg != null) { 1578 throw new IllegalArgumentException(name); 1579 } 1580 pkg = new Package(name, specTitle, specVersion, specVendor, 1581 implTitle, implVersion, implVendor, 1582 sealBase, this); 1583 // Races here can be safely dealt with by ensuring we always return 1584 // the same package object 1585 Package oldPkg = packages.putIfAbsent(name, pkg); 1586 return (oldPkg != null ? oldPkg : pkg); 1587 } 1588 1589 /** 1590 * Returns a <tt>Package</tt> that has been defined by this class loader 1591 * or any of its ancestors. 1592 * 1593 * @param name 1594 * The package name 1595 * 1596 * @return The <tt>Package</tt> corresponding to the given name, or 1597 * <tt>null</tt> if not found 1598 * 1599 * @since 1.2 1600 */ 1601 protected Package getPackage(String name) { 1602 Package pkg = packages.get(name); 1603 if (pkg == null) { 1604 if (parent != null) { 1605 pkg = parent.getPackage(name); 1606 } else { 1607 pkg = Package.getSystemPackage(name); 1608 } 1609 } 1610 return pkg; 1611 } 1612 1613 /** 1614 * Returns all of the <tt>Packages</tt> defined by this class loader and 1615 * its ancestors. 1616 * 1617 * @return The array of <tt>Package</tt> objects defined by this 1618 * <tt>ClassLoader</tt> 1619 * 1620 * @since 1.2 1621 */ 1622 protected Package[] getPackages() { 1623 Map<String, Package> map; 1624 Package[] pkgs; 1625 if (parent != null) { 1626 pkgs = parent.getPackages(); 1627 } else { 1628 pkgs = Package.getSystemPackages(); 1629 } 1630 1631 if (pkgs == null) { 1632 map = packages; 1633 } else { 1634 map = new HashMap<>(packages); 1635 for (Package pkg : pkgs) { 1636 String pkgName = pkg.getName(); 1637 if (!map.containsKey(pkgName)) { 1638 map.put(pkgName, pkg); 1639 } 1640 } 1641 } 1642 return map.values().toArray(new Package[map.size()]); 1643 1644 } 1645 1646 1647 // -- Native library access -- 1648 1649 /** 1650 * Returns the absolute path name of a native library. The VM invokes this 1651 * method to locate the native libraries that belong to classes loaded with 1652 * this class loader. If this method returns <tt>null</tt>, the VM 1653 * searches the library along the path specified as the 1654 * "<tt>java.library.path</tt>" property. 1655 * 1656 * @param libname 1657 * The library name 1658 * 1659 * @return The absolute path of the native library 1660 * 1661 * @see System#loadLibrary(String) 1662 * @see System#mapLibraryName(String) 1663 * 1664 * @since 1.2 1665 */ 1666 protected String findLibrary(String libname) { 1667 return null; 1668 } 1669 1670 /** 1671 * The inner class NativeLibrary denotes a loaded native library instance. 1672 * Every classloader contains a vector of loaded native libraries in the 1673 * private field <tt>nativeLibraries</tt>. The native libraries loaded 1674 * into the system are entered into the <tt>systemNativeLibraries</tt> 1675 * vector. 1676 * 1677 * <p> Every native library requires a particular version of JNI. This is 1678 * denoted by the private <tt>jniVersion</tt> field. This field is set by 1679 * the VM when it loads the library, and used by the VM to pass the correct 1680 * version of JNI to the native methods. </p> 1681 * 1682 * @see ClassLoader 1683 * @since 1.2 1684 */ 1685 static class NativeLibrary { 1686 // opaque handle to native library, used in native code. 1687 long handle; 1688 // the version of JNI environment the native library requires. 1689 private int jniVersion; 1690 // the class from which the library is loaded, also indicates 1691 // the loader this native library belongs. 1692 private final Class<?> fromClass; 1693 // the canonicalized name of the native library. 1694 // or static library name 1695 String name; 1696 // Indicates if the native library is linked into the VM 1697 boolean isBuiltin; 1698 // Indicates if the native library is loaded 1699 boolean loaded; 1700 native void load(String name, boolean isBuiltin); 1701 1702 native long find(String name); 1703 native void unload(String name, boolean isBuiltin); 1704 static native String findBuiltinLib(String name); 1705 1706 public NativeLibrary(Class<?> fromClass, String name, boolean isBuiltin) { 1707 this.name = name; 1708 this.fromClass = fromClass; 1709 this.isBuiltin = isBuiltin; 1710 } 1711 1712 protected void finalize() { 1713 synchronized (loadedLibraryNames) { 1714 if (fromClass.getClassLoader() != null && loaded) { 1715 /* remove the native library name */ 1716 int size = loadedLibraryNames.size(); 1717 for (int i = 0; i < size; i++) { 1718 if (name.equals(loadedLibraryNames.elementAt(i))) { 1719 loadedLibraryNames.removeElementAt(i); 1720 break; 1721 } 1722 } 1723 /* unload the library. */ 1724 ClassLoader.nativeLibraryContext.push(this); 1725 try { 1726 unload(name, isBuiltin); 1727 } finally { 1728 ClassLoader.nativeLibraryContext.pop(); 1729 } 1730 } 1731 } 1732 } 1733 // Invoked in the VM to determine the context class in 1734 // JNI_Load/JNI_Unload 1735 static Class<?> getFromClass() { 1736 return ClassLoader.nativeLibraryContext.peek().fromClass; 1737 } 1738 } 1739 1740 // All native library names we've loaded. 1741 private static Vector<String> loadedLibraryNames = new Vector<>(); 1742 1743 // Native libraries belonging to system classes. 1744 private static Vector<NativeLibrary> systemNativeLibraries 1745 = new Vector<>(); 1746 1747 // Native libraries associated with the class loader. 1748 private Vector<NativeLibrary> nativeLibraries = new Vector<>(); 1749 1750 // native libraries being loaded/unloaded. 1751 private static Stack<NativeLibrary> nativeLibraryContext = new Stack<>(); 1752 1753 // The paths searched for libraries 1754 private static String usr_paths[]; 1755 private static String sys_paths[]; 1756 1757 private static String[] initializePath(String propname) { 1758 String ldpath = System.getProperty(propname, ""); 1759 String ps = File.pathSeparator; 1760 int ldlen = ldpath.length(); 1761 int i, j, n; 1762 // Count the separators in the path 1763 i = ldpath.indexOf(ps); 1764 n = 0; 1765 while (i >= 0) { 1766 n++; 1767 i = ldpath.indexOf(ps, i + 1); 1768 } 1769 1770 // allocate the array of paths - n :'s = n + 1 path elements 1771 String[] paths = new String[n + 1]; 1772 1773 // Fill the array with paths from the ldpath 1774 n = i = 0; 1775 j = ldpath.indexOf(ps); 1776 while (j >= 0) { 1777 if (j - i > 0) { 1778 paths[n++] = ldpath.substring(i, j); 1779 } else if (j - i == 0) { 1780 paths[n++] = "."; 1781 } 1782 i = j + 1; 1783 j = ldpath.indexOf(ps, i); 1784 } 1785 paths[n] = ldpath.substring(i, ldlen); 1786 return paths; 1787 } 1788 1789 // Invoked in the java.lang.Runtime class to implement load and loadLibrary. 1790 static void loadLibrary(Class<?> fromClass, String name, 1791 boolean isAbsolute) { 1792 ClassLoader loader = 1793 (fromClass == null) ? null : fromClass.getClassLoader(); 1794 if (sys_paths == null) { 1795 usr_paths = initializePath("java.library.path"); 1796 sys_paths = initializePath("sun.boot.library.path"); 1797 } 1798 if (isAbsolute) { 1799 if (loadLibrary0(fromClass, new File(name))) { 1800 return; 1801 } 1802 throw new UnsatisfiedLinkError("Can't load library: " + name); 1803 } 1804 if (loader != null) { 1805 String libfilename = loader.findLibrary(name); 1806 if (libfilename != null) { 1807 File libfile = new File(libfilename); 1808 if (!libfile.isAbsolute()) { 1809 throw new UnsatisfiedLinkError( 1810 "ClassLoader.findLibrary failed to return an absolute path: " + libfilename); 1811 } 1812 if (loadLibrary0(fromClass, libfile)) { 1813 return; 1814 } 1815 throw new UnsatisfiedLinkError("Can't load " + libfilename); 1816 } 1817 } 1818 for (String sys_path : sys_paths) { 1819 File libfile = new File(sys_path, System.mapLibraryName(name)); 1820 if (loadLibrary0(fromClass, libfile)) { 1821 return; 1822 } 1823 libfile = ClassLoaderHelper.mapAlternativeName(libfile); 1824 if (libfile != null && loadLibrary0(fromClass, libfile)) { 1825 return; 1826 } 1827 } 1828 if (loader != null) { 1829 for (String usr_path : usr_paths) { 1830 File libfile = new File(usr_path, System.mapLibraryName(name)); 1831 if (loadLibrary0(fromClass, libfile)) { 1832 return; 1833 } 1834 libfile = ClassLoaderHelper.mapAlternativeName(libfile); 1835 if (libfile != null && loadLibrary0(fromClass, libfile)) { 1836 return; 1837 } 1838 } 1839 } 1840 // Oops, it failed 1841 throw new UnsatisfiedLinkError("no " + name + " in java.library.path"); 1842 } 1843 1844 private static boolean loadLibrary0(Class<?> fromClass, final File file) { 1845 // Check to see if we're attempting to access a static library 1846 String name = NativeLibrary.findBuiltinLib(file.getName()); 1847 boolean isBuiltin = (name != null); 1848 if (!isBuiltin) { 1849 name = AccessController.doPrivileged( 1850 new PrivilegedAction<String>() { 1851 public String run() { 1852 try { 1853 return file.exists() ? file.getCanonicalPath() : null; 1854 } catch (IOException e) { 1855 return null; 1856 } 1857 } 1858 }); 1859 if (name == null) { 1860 return false; 1861 } 1862 } 1863 ClassLoader loader = 1864 (fromClass == null) ? null : fromClass.getClassLoader(); 1865 Vector<NativeLibrary> libs = 1866 loader != null ? loader.nativeLibraries : systemNativeLibraries; 1867 synchronized (libs) { 1868 int size = libs.size(); 1869 for (int i = 0; i < size; i++) { 1870 NativeLibrary lib = libs.elementAt(i); 1871 if (name.equals(lib.name)) { 1872 return true; 1873 } 1874 } 1875 1876 synchronized (loadedLibraryNames) { 1877 if (loadedLibraryNames.contains(name)) { 1878 throw new UnsatisfiedLinkError 1879 ("Native Library " + 1880 name + 1881 " already loaded in another classloader"); 1882 } 1883 /* If the library is being loaded (must be by the same thread, 1884 * because Runtime.load and Runtime.loadLibrary are 1885 * synchronous). The reason is can occur is that the JNI_OnLoad 1886 * function can cause another loadLibrary invocation. 1887 * 1888 * Thus we can use a static stack to hold the list of libraries 1889 * we are loading. 1890 * 1891 * If there is a pending load operation for the library, we 1892 * immediately return success; otherwise, we raise 1893 * UnsatisfiedLinkError. 1894 */ 1895 int n = nativeLibraryContext.size(); 1896 for (int i = 0; i < n; i++) { 1897 NativeLibrary lib = nativeLibraryContext.elementAt(i); 1898 if (name.equals(lib.name)) { 1899 if (loader == lib.fromClass.getClassLoader()) { 1900 return true; 1901 } else { 1902 throw new UnsatisfiedLinkError 1903 ("Native Library " + 1904 name + 1905 " is being loaded in another classloader"); 1906 } 1907 } 1908 } 1909 NativeLibrary lib = new NativeLibrary(fromClass, name, isBuiltin); 1910 nativeLibraryContext.push(lib); 1911 try { 1912 lib.load(name, isBuiltin); 1913 } finally { 1914 nativeLibraryContext.pop(); 1915 } 1916 if (lib.loaded) { 1917 loadedLibraryNames.addElement(name); 1918 libs.addElement(lib); 1919 return true; 1920 } 1921 return false; 1922 } 1923 } 1924 } 1925 1926 // Invoked in the VM class linking code. 1927 static long findNative(ClassLoader loader, String name) { 1928 Vector<NativeLibrary> libs = 1929 loader != null ? loader.nativeLibraries : systemNativeLibraries; 1930 synchronized (libs) { 1931 int size = libs.size(); 1932 for (int i = 0; i < size; i++) { 1933 NativeLibrary lib = libs.elementAt(i); 1934 long entry = lib.find(name); 1935 if (entry != 0) 1936 return entry; 1937 } 1938 } 1939 return 0; 1940 } 1941 1942 1943 // -- Assertion management -- 1944 1945 final Object assertionLock; 1946 1947 // The default toggle for assertion checking. 1948 // @GuardedBy("assertionLock") 1949 private boolean defaultAssertionStatus = false; 1950 1951 // Maps String packageName to Boolean package default assertion status Note 1952 // that the default package is placed under a null map key. If this field 1953 // is null then we are delegating assertion status queries to the VM, i.e., 1954 // none of this ClassLoader's assertion status modification methods have 1955 // been invoked. 1956 // @GuardedBy("assertionLock") 1957 private Map<String, Boolean> packageAssertionStatus = null; 1958 1959 // Maps String fullyQualifiedClassName to Boolean assertionStatus If this 1960 // field is null then we are delegating assertion status queries to the VM, 1961 // i.e., none of this ClassLoader's assertion status modification methods 1962 // have been invoked. 1963 // @GuardedBy("assertionLock") 1964 Map<String, Boolean> classAssertionStatus = null; 1965 1966 /** 1967 * Sets the default assertion status for this class loader. This setting 1968 * determines whether classes loaded by this class loader and initialized 1969 * in the future will have assertions enabled or disabled by default. 1970 * This setting may be overridden on a per-package or per-class basis by 1971 * invoking {@link #setPackageAssertionStatus(String, boolean)} or {@link 1972 * #setClassAssertionStatus(String, boolean)}. 1973 * 1974 * @param enabled 1975 * <tt>true</tt> if classes loaded by this class loader will 1976 * henceforth have assertions enabled by default, <tt>false</tt> 1977 * if they will have assertions disabled by default. 1978 * 1979 * @since 1.4 1980 */ 1981 public void setDefaultAssertionStatus(boolean enabled) { 1982 synchronized (assertionLock) { 1983 if (classAssertionStatus == null) 1984 initializeJavaAssertionMaps(); 1985 1986 defaultAssertionStatus = enabled; 1987 } 1988 } 1989 1990 /** 1991 * Sets the package default assertion status for the named package. The 1992 * package default assertion status determines the assertion status for 1993 * classes initialized in the future that belong to the named package or 1994 * any of its "subpackages". 1995 * 1996 * <p> A subpackage of a package named p is any package whose name begins 1997 * with "<tt>p.</tt>". For example, <tt>javax.swing.text</tt> is a 1998 * subpackage of <tt>javax.swing</tt>, and both <tt>java.util</tt> and 1999 * <tt>java.lang.reflect</tt> are subpackages of <tt>java</tt>. 2000 * 2001 * <p> In the event that multiple package defaults apply to a given class, 2002 * the package default pertaining to the most specific package takes 2003 * precedence over the others. For example, if <tt>javax.lang</tt> and 2004 * <tt>javax.lang.reflect</tt> both have package defaults associated with 2005 * them, the latter package default applies to classes in 2006 * <tt>javax.lang.reflect</tt>. 2007 * 2008 * <p> Package defaults take precedence over the class loader's default 2009 * assertion status, and may be overridden on a per-class basis by invoking 2010 * {@link #setClassAssertionStatus(String, boolean)}. </p> 2011 * 2012 * @param packageName 2013 * The name of the package whose package default assertion status 2014 * is to be set. A <tt>null</tt> value indicates the unnamed 2015 * package that is "current" 2016 * (see section 7.4.2 of 2017 * <cite>The Java™ Language Specification</cite>.) 2018 * 2019 * @param enabled 2020 * <tt>true</tt> if classes loaded by this classloader and 2021 * belonging to the named package or any of its subpackages will 2022 * have assertions enabled by default, <tt>false</tt> if they will 2023 * have assertions disabled by default. 2024 * 2025 * @since 1.4 2026 */ 2027 public void setPackageAssertionStatus(String packageName, 2028 boolean enabled) { 2029 synchronized (assertionLock) { 2030 if (packageAssertionStatus == null) 2031 initializeJavaAssertionMaps(); 2032 2033 packageAssertionStatus.put(packageName, enabled); 2034 } 2035 } 2036 2037 /** 2038 * Sets the desired assertion status for the named top-level class in this 2039 * class loader and any nested classes contained therein. This setting 2040 * takes precedence over the class loader's default assertion status, and 2041 * over any applicable per-package default. This method has no effect if 2042 * the named class has already been initialized. (Once a class is 2043 * initialized, its assertion status cannot change.) 2044 * 2045 * <p> If the named class is not a top-level class, this invocation will 2046 * have no effect on the actual assertion status of any class. </p> 2047 * 2048 * @param className 2049 * The fully qualified class name of the top-level class whose 2050 * assertion status is to be set. 2051 * 2052 * @param enabled 2053 * <tt>true</tt> if the named class is to have assertions 2054 * enabled when (and if) it is initialized, <tt>false</tt> if the 2055 * class is to have assertions disabled. 2056 * 2057 * @since 1.4 2058 */ 2059 public void setClassAssertionStatus(String className, boolean enabled) { 2060 synchronized (assertionLock) { 2061 if (classAssertionStatus == null) 2062 initializeJavaAssertionMaps(); 2063 2064 classAssertionStatus.put(className, enabled); 2065 } 2066 } 2067 2068 /** 2069 * Sets the default assertion status for this class loader to 2070 * <tt>false</tt> and discards any package defaults or class assertion 2071 * status settings associated with the class loader. This method is 2072 * provided so that class loaders can be made to ignore any command line or 2073 * persistent assertion status settings and "start with a clean slate." 2074 * 2075 * @since 1.4 2076 */ 2077 public void clearAssertionStatus() { 2078 /* 2079 * Whether or not "Java assertion maps" are initialized, set 2080 * them to empty maps, effectively ignoring any present settings. 2081 */ 2082 synchronized (assertionLock) { 2083 classAssertionStatus = new HashMap<>(); 2084 packageAssertionStatus = new HashMap<>(); 2085 defaultAssertionStatus = false; 2086 } 2087 } 2088 2089 /** 2090 * Returns the assertion status that would be assigned to the specified 2091 * class if it were to be initialized at the time this method is invoked. 2092 * If the named class has had its assertion status set, the most recent 2093 * setting will be returned; otherwise, if any package default assertion 2094 * status pertains to this class, the most recent setting for the most 2095 * specific pertinent package default assertion status is returned; 2096 * otherwise, this class loader's default assertion status is returned. 2097 * </p> 2098 * 2099 * @param className 2100 * The fully qualified class name of the class whose desired 2101 * assertion status is being queried. 2102 * 2103 * @return The desired assertion status of the specified class. 2104 * 2105 * @see #setClassAssertionStatus(String, boolean) 2106 * @see #setPackageAssertionStatus(String, boolean) 2107 * @see #setDefaultAssertionStatus(boolean) 2108 * 2109 * @since 1.4 2110 */ 2111 boolean desiredAssertionStatus(String className) { 2112 synchronized (assertionLock) { 2113 // assert classAssertionStatus != null; 2114 // assert packageAssertionStatus != null; 2115 2116 // Check for a class entry 2117 Boolean result = classAssertionStatus.get(className); 2118 if (result != null) 2119 return result.booleanValue(); 2120 2121 // Check for most specific package entry 2122 int dotIndex = className.lastIndexOf('.'); 2123 if (dotIndex < 0) { // default package 2124 result = packageAssertionStatus.get(null); 2125 if (result != null) 2126 return result.booleanValue(); 2127 } 2128 while(dotIndex > 0) { 2129 className = className.substring(0, dotIndex); 2130 result = packageAssertionStatus.get(className); 2131 if (result != null) 2132 return result.booleanValue(); 2133 dotIndex = className.lastIndexOf('.', dotIndex-1); 2134 } 2135 2136 // Return the classloader default 2137 return defaultAssertionStatus; 2138 } 2139 } 2140 2141 // Set up the assertions with information provided by the VM. 2142 // Note: Should only be called inside a synchronized block 2143 private void initializeJavaAssertionMaps() { 2144 // assert Thread.holdsLock(assertionLock); 2145 2146 classAssertionStatus = new HashMap<>(); 2147 packageAssertionStatus = new HashMap<>(); 2148 AssertionStatusDirectives directives = retrieveDirectives(); 2149 2150 for(int i = 0; i < directives.classes.length; i++) 2151 classAssertionStatus.put(directives.classes[i], 2152 directives.classEnabled[i]); 2153 2154 for(int i = 0; i < directives.packages.length; i++) 2155 packageAssertionStatus.put(directives.packages[i], 2156 directives.packageEnabled[i]); 2157 2158 defaultAssertionStatus = directives.deflt; 2159 } 2160 2161 // Retrieves the assertion directives from the VM. 2162 private static native AssertionStatusDirectives retrieveDirectives(); 2163 } 2164 2165 2166 class SystemClassLoaderAction 2167 implements PrivilegedExceptionAction<ClassLoader> { 2168 private ClassLoader parent; 2169 2170 SystemClassLoaderAction(ClassLoader parent) { 2171 this.parent = parent; 2172 } 2173 2174 public ClassLoader run() throws Exception { 2175 String cls = System.getProperty("java.system.class.loader"); 2176 if (cls == null) { 2177 return parent; 2178 } 2179 2180 Constructor<?> ctor = Class.forName(cls, true, parent) 2181 .getDeclaredConstructor(new Class<?>[] { ClassLoader.class }); 2182 ClassLoader sys = (ClassLoader) ctor.newInstance( 2183 new Object[] { parent }); 2184 Thread.currentThread().setContextClassLoader(sys); 2185 return sys; 2186 } 2187 }