1 /* 2 * Copyright (c) 1997, 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 26 package java.net; 27 28 import java.io.Closeable; 29 import java.io.File; 30 import java.io.FilePermission; 31 import java.io.IOException; 32 import java.io.InputStream; 33 import java.security.AccessControlContext; 34 import java.security.AccessController; 35 import java.security.CodeSigner; 36 import java.security.CodeSource; 37 import java.security.Permission; 38 import java.security.PermissionCollection; 39 import java.security.PrivilegedAction; 40 import java.security.PrivilegedExceptionAction; 41 import java.security.SecureClassLoader; 42 import java.util.Enumeration; 43 import java.util.List; 44 import java.util.NoSuchElementException; 45 import java.util.Objects; 46 import java.util.Set; 47 import java.util.WeakHashMap; 48 import java.util.jar.Attributes; 49 import java.util.jar.Attributes.Name; 50 import java.util.jar.JarFile; 51 import java.util.jar.Manifest; 52 import sun.misc.Resource; 53 import sun.misc.URLClassPath; 54 import sun.net.www.ParseUtil; 55 import sun.security.util.SecurityConstants; 56 57 /** 58 * This class loader is used to load classes and resources from a search 59 * path of URLs referring to both JAR files and directories. Any URL that 60 * ends with a '/' is assumed to refer to a directory. Otherwise, the URL 61 * is assumed to refer to a JAR file which will be opened as needed. 62 * <p> 63 * The AccessControlContext of the thread that created the instance of 64 * URLClassLoader will be used when subsequently loading classes and 65 * resources. 66 * <p> 67 * The classes that are loaded are by default granted permission only to 68 * access the URLs specified when the URLClassLoader was created. 69 * 70 * @author David Connelly 71 * @since 1.2 72 */ 73 public class URLClassLoader extends SecureClassLoader implements Closeable { 74 /* The search path for classes and resources */ 75 private final URLClassPath ucp; 76 77 /* The context to be used when loading classes and resources */ 78 private final AccessControlContext acc; 79 80 /** 81 * Constructs a new URLClassLoader for the given URLs. The URLs will be 82 * searched in the order specified for classes and resources after first 83 * searching in the specified parent class loader. Any URL that ends with 84 * a '/' is assumed to refer to a directory. Otherwise, the URL is assumed 85 * to refer to a JAR file which will be downloaded and opened as needed. 86 * 87 * <p>If there is a security manager, this method first 88 * calls the security manager's {@code checkCreateClassLoader} method 89 * to ensure creation of a class loader is allowed. 90 * 91 * @param urls the URLs from which to load classes and resources 92 * @param parent the parent class loader for delegation 93 * @exception SecurityException if a security manager exists and its 94 * {@code checkCreateClassLoader} method doesn't allow 95 * creation of a class loader. 96 * @exception NullPointerException if {@code urls} is {@code null}. 97 * @see SecurityManager#checkCreateClassLoader 98 */ 99 public URLClassLoader(URL[] urls, ClassLoader parent) { 100 super(parent); 101 // this is to make the stack depth consistent with 1.1 102 SecurityManager security = System.getSecurityManager(); 103 if (security != null) { 104 security.checkCreateClassLoader(); 105 } 106 ucp = new URLClassPath(urls); 107 this.acc = AccessController.getContext(); 108 } 109 110 URLClassLoader(URL[] urls, ClassLoader parent, 111 AccessControlContext acc) { 112 super(parent); 113 // this is to make the stack depth consistent with 1.1 114 SecurityManager security = System.getSecurityManager(); 115 if (security != null) { 116 security.checkCreateClassLoader(); 117 } 118 ucp = new URLClassPath(urls); 119 this.acc = acc; 120 } 121 122 /** 123 * Constructs a new URLClassLoader for the specified URLs using the 124 * default delegation parent {@code ClassLoader}. The URLs will 125 * be searched in the order specified for classes and resources after 126 * first searching in the parent class loader. Any URL that ends with 127 * a '/' is assumed to refer to a directory. Otherwise, the URL is 128 * assumed to refer to a JAR file which will be downloaded and opened 129 * as needed. 130 * 131 * <p>If there is a security manager, this method first 132 * calls the security manager's {@code checkCreateClassLoader} method 133 * to ensure creation of a class loader is allowed. 134 * 135 * @param urls the URLs from which to load classes and resources 136 * 137 * @exception SecurityException if a security manager exists and its 138 * {@code checkCreateClassLoader} method doesn't allow 139 * creation of a class loader. 140 * @exception NullPointerException if {@code urls} is {@code null}. 141 * @see SecurityManager#checkCreateClassLoader 142 */ 143 public URLClassLoader(URL[] urls) { 144 super(); 145 // this is to make the stack depth consistent with 1.1 146 SecurityManager security = System.getSecurityManager(); 147 if (security != null) { 148 security.checkCreateClassLoader(); 149 } 150 ucp = new URLClassPath(urls); 151 this.acc = AccessController.getContext(); 152 } 153 154 URLClassLoader(URL[] urls, AccessControlContext acc) { 155 super(); 156 // this is to make the stack depth consistent with 1.1 157 SecurityManager security = System.getSecurityManager(); 158 if (security != null) { 159 security.checkCreateClassLoader(); 160 } 161 ucp = new URLClassPath(urls); 162 this.acc = acc; 163 } 164 165 /** 166 * Constructs a new URLClassLoader for the specified URLs, parent 167 * class loader, and URLStreamHandlerFactory. The parent argument 168 * will be used as the parent class loader for delegation. The 169 * factory argument will be used as the stream handler factory to 170 * obtain protocol handlers when creating new jar URLs. 171 * 172 * <p>If there is a security manager, this method first 173 * calls the security manager's {@code checkCreateClassLoader} method 174 * to ensure creation of a class loader is allowed. 175 * 176 * @param urls the URLs from which to load classes and resources 177 * @param parent the parent class loader for delegation 178 * @param factory the URLStreamHandlerFactory to use when creating URLs 179 * 180 * @exception SecurityException if a security manager exists and its 181 * {@code checkCreateClassLoader} method doesn't allow 182 * creation of a class loader. 183 * @exception NullPointerException if {@code urls} is {@code null}. 184 * @see SecurityManager#checkCreateClassLoader 185 */ 186 public URLClassLoader(URL[] urls, ClassLoader parent, 187 URLStreamHandlerFactory factory) { 188 super(parent); 189 // this is to make the stack depth consistent with 1.1 190 SecurityManager security = System.getSecurityManager(); 191 if (security != null) { 192 security.checkCreateClassLoader(); 193 } 194 ucp = new URLClassPath(urls, factory); 195 acc = AccessController.getContext(); 196 } 197 198 /* A map (used as a set) to keep track of closeable local resources 199 * (either JarFiles or FileInputStreams). We don't care about 200 * Http resources since they don't need to be closed. 201 * 202 * If the resource is coming from a jar file 203 * we keep a (weak) reference to the JarFile object which can 204 * be closed if URLClassLoader.close() called. Due to jar file 205 * caching there will typically be only one JarFile object 206 * per underlying jar file. 207 * 208 * For file resources, which is probably a less common situation 209 * we have to keep a weak reference to each stream. 210 */ 211 212 private WeakHashMap<Closeable,Void> 213 closeables = new WeakHashMap<>(); 214 215 /** 216 * Returns an input stream for reading the specified resource. 217 * If this loader is closed, then any resources opened by this method 218 * will be closed. 219 * 220 * <p> The search order is described in the documentation for {@link 221 * #getResource(String)}. </p> 222 * 223 * @param name 224 * The resource name 225 * 226 * @return An input stream for reading the resource, or {@code null} 227 * if the resource could not be found 228 * 229 * @since 1.7 230 */ 231 public InputStream getResourceAsStream(String name) { 232 URL url = getResource(name); 233 try { 234 if (url == null) { 235 return null; 236 } 237 URLConnection urlc = url.openConnection(); 238 InputStream is = urlc.getInputStream(); 239 if (urlc instanceof JarURLConnection) { 240 JarURLConnection juc = (JarURLConnection)urlc; 241 JarFile jar = juc.getJarFile(); 242 synchronized (closeables) { 243 if (!closeables.containsKey(jar)) { 244 closeables.put(jar, null); 245 } 246 } 247 } else if (urlc instanceof sun.net.www.protocol.file.FileURLConnection) { 248 synchronized (closeables) { 249 closeables.put(is, null); 250 } 251 } 252 return is; 253 } catch (IOException e) { 254 return null; 255 } 256 } 257 258 /** 259 * Closes this URLClassLoader, so that it can no longer be used to load 260 * new classes or resources that are defined by this loader. 261 * Classes and resources defined by any of this loader's parents in the 262 * delegation hierarchy are still accessible. Also, any classes or resources 263 * that are already loaded, are still accessible. 264 * <p> 265 * In the case of jar: and file: URLs, it also closes any files 266 * that were opened by it. If another thread is loading a 267 * class when the {@code close} method is invoked, then the result of 268 * that load is undefined. 269 * <p> 270 * The method makes a best effort attempt to close all opened files, 271 * by catching {@link IOException}s internally. Unchecked exceptions 272 * and errors are not caught. Calling close on an already closed 273 * loader has no effect. 274 * 275 * @exception IOException if closing any file opened by this class loader 276 * resulted in an IOException. Any such exceptions are caught internally. 277 * If only one is caught, then it is re-thrown. If more than one exception 278 * is caught, then the second and following exceptions are added 279 * as suppressed exceptions of the first one caught, which is then re-thrown. 280 * 281 * @exception SecurityException if a security manager is set, and it denies 282 * {@link RuntimePermission}{@code ("closeClassLoader")} 283 * 284 * @since 1.7 285 */ 286 public void close() throws IOException { 287 SecurityManager security = System.getSecurityManager(); 288 if (security != null) { 289 security.checkPermission(new RuntimePermission("closeClassLoader")); 290 } 291 List<IOException> errors = ucp.closeLoaders(); 292 293 // now close any remaining streams. 294 295 synchronized (closeables) { 296 Set<Closeable> keys = closeables.keySet(); 297 for (Closeable c : keys) { 298 try { 299 c.close(); 300 } catch (IOException ioex) { 301 errors.add(ioex); 302 } 303 } 304 closeables.clear(); 305 } 306 307 if (errors.isEmpty()) { 308 return; 309 } 310 311 IOException firstex = errors.remove(0); 312 313 // Suppress any remaining exceptions 314 315 for (IOException error: errors) { 316 firstex.addSuppressed(error); 317 } 318 throw firstex; 319 } 320 321 /** 322 * Appends the specified URL to the list of URLs to search for 323 * classes and resources. 324 * <p> 325 * If the URL specified is {@code null} or is already in the 326 * list of URLs, or if this loader is closed, then invoking this 327 * method has no effect. 328 * 329 * @param url the URL to be added to the search path of URLs 330 */ 331 protected void addURL(URL url) { 332 ucp.addURL(url); 333 } 334 335 /** 336 * Returns the search path of URLs for loading classes and resources. 337 * This includes the original list of URLs specified to the constructor, 338 * along with any URLs subsequently appended by the addURL() method. 339 * @return the search path of URLs for loading classes and resources. 340 */ 341 public URL[] getURLs() { 342 return ucp.getURLs(); 343 } 344 345 /** 346 * Finds and loads the class with the specified name from the URL search 347 * path. Any URLs referring to JAR files are loaded and opened as needed 348 * until the class is found. 349 * 350 * @param name the name of the class 351 * @return the resulting class 352 * @exception ClassNotFoundException if the class could not be found, 353 * or if the loader is closed. 354 * @exception NullPointerException if {@code name} is {@code null}. 355 */ 356 protected Class<?> findClass(final String name) 357 throws ClassNotFoundException 358 { 359 try { 360 return AccessController.doPrivileged( 361 new PrivilegedExceptionAction<Class<?>>() { 362 public Class<?> run() throws ClassNotFoundException { 363 String path = name.replace('.', '/').concat(".class"); 364 Resource res = ucp.getResource(path, false); 365 if (res != null) { 366 try { 367 return defineClass(name, res); 368 } catch (IOException e) { 369 throw new ClassNotFoundException(name, e); 370 } 371 } else { 372 throw new ClassNotFoundException(name); 373 } 374 } 375 }, acc); 376 } catch (java.security.PrivilegedActionException pae) { 377 throw (ClassNotFoundException) pae.getException(); 378 } 379 } 380 381 /* 382 * Retrieve the package using the specified package name. 383 * If non-null, verify the package using the specified code 384 * source and manifest. 385 */ 386 private Package getAndVerifyPackage(String pkgname, 387 Manifest man, URL url) { 388 Package pkg = getPackage(pkgname); 389 if (pkg != null) { 390 // Package found, so check package sealing. 391 if (pkg.isSealed()) { 392 // Verify that code source URL is the same. 393 if (!pkg.isSealed(url)) { 394 throw new SecurityException( 395 "sealing violation: package " + pkgname + " is sealed"); 396 } 397 } else { 398 // Make sure we are not attempting to seal the package 399 // at this code source URL. 400 if ((man != null) && isSealed(pkgname, man)) { 401 throw new SecurityException( 402 "sealing violation: can't seal package " + pkgname + 403 ": already loaded"); 404 } 405 } 406 } 407 return pkg; 408 } 409 410 /* 411 * Defines a Class using the class bytes obtained from the specified 412 * Resource. The resulting Class must be resolved before it can be 413 * used. 414 */ 415 private Class<?> defineClass(String name, Resource res) throws IOException { 416 long t0 = System.nanoTime(); 417 int i = name.lastIndexOf('.'); 418 URL url = res.getCodeSourceURL(); 419 if (i != -1) { 420 String pkgname = name.substring(0, i); 421 // Check if package already loaded. 422 Manifest man = res.getManifest(); 423 if (getAndVerifyPackage(pkgname, man, url) == null) { 424 try { 425 if (man != null) { 426 definePackage(pkgname, man, url); 427 } else { 428 definePackage(pkgname, null, null, null, null, null, null, null); 429 } 430 } catch (IllegalArgumentException iae) { 431 // parallel-capable class loaders: re-verify in case of a 432 // race condition 433 if (getAndVerifyPackage(pkgname, man, url) == null) { 434 // Should never happen 435 throw new AssertionError("Cannot find package " + 436 pkgname); 437 } 438 } 439 } 440 } 441 // Now read the class bytes and define the class 442 java.nio.ByteBuffer bb = res.getByteBuffer(); 443 if (bb != null) { 444 // Use (direct) ByteBuffer: 445 CodeSigner[] signers = res.getCodeSigners(); 446 CodeSource cs = new CodeSource(url, signers); 447 sun.misc.PerfCounter.getReadClassBytesTime().addElapsedTimeFrom(t0); 448 return defineClass(name, bb, cs); 449 } else { 450 byte[] b = res.getBytes(); 451 // must read certificates AFTER reading bytes. 452 CodeSigner[] signers = res.getCodeSigners(); 453 CodeSource cs = new CodeSource(url, signers); 454 sun.misc.PerfCounter.getReadClassBytesTime().addElapsedTimeFrom(t0); 455 return defineClass(name, b, 0, b.length, cs); 456 } 457 } 458 459 /** 460 * Defines a new package by name in this ClassLoader. The attributes 461 * contained in the specified Manifest will be used to obtain package 462 * version and sealing information. For sealed packages, the additional 463 * URL specifies the code source URL from which the package was loaded. 464 * 465 * @param name the package name 466 * @param man the Manifest containing package version and sealing 467 * information 468 * @param url the code source url for the package, or null if none 469 * @exception IllegalArgumentException if the package name duplicates 470 * an existing package either in this class loader or one 471 * of its ancestors 472 * @return the newly defined Package object 473 */ 474 protected Package definePackage(String name, Manifest man, URL url) 475 throws IllegalArgumentException 476 { 477 String path = name.replace('.', '/').concat("/"); 478 String specTitle = null, specVersion = null, specVendor = null; 479 String implTitle = null, implVersion = null, implVendor = null; 480 String sealed = null; 481 URL sealBase = null; 482 483 Attributes attr = man.getAttributes(path); 484 if (attr != null) { 485 specTitle = attr.getValue(Name.SPECIFICATION_TITLE); 486 specVersion = attr.getValue(Name.SPECIFICATION_VERSION); 487 specVendor = attr.getValue(Name.SPECIFICATION_VENDOR); 488 implTitle = attr.getValue(Name.IMPLEMENTATION_TITLE); 489 implVersion = attr.getValue(Name.IMPLEMENTATION_VERSION); 490 implVendor = attr.getValue(Name.IMPLEMENTATION_VENDOR); 491 sealed = attr.getValue(Name.SEALED); 492 } 493 attr = man.getMainAttributes(); 494 if (attr != null) { 495 if (specTitle == null) { 496 specTitle = attr.getValue(Name.SPECIFICATION_TITLE); 497 } 498 if (specVersion == null) { 499 specVersion = attr.getValue(Name.SPECIFICATION_VERSION); 500 } 501 if (specVendor == null) { 502 specVendor = attr.getValue(Name.SPECIFICATION_VENDOR); 503 } 504 if (implTitle == null) { 505 implTitle = attr.getValue(Name.IMPLEMENTATION_TITLE); 506 } 507 if (implVersion == null) { 508 implVersion = attr.getValue(Name.IMPLEMENTATION_VERSION); 509 } 510 if (implVendor == null) { 511 implVendor = attr.getValue(Name.IMPLEMENTATION_VENDOR); 512 } 513 if (sealed == null) { 514 sealed = attr.getValue(Name.SEALED); 515 } 516 } 517 if ("true".equalsIgnoreCase(sealed)) { 518 sealBase = url; 519 } 520 return definePackage(name, specTitle, specVersion, specVendor, 521 implTitle, implVersion, implVendor, sealBase); 522 } 523 524 /* 525 * Returns true if the specified package name is sealed according to the 526 * given manifest. 527 */ 528 private boolean isSealed(String name, Manifest man) { 529 String path = name.replace('.', '/').concat("/"); 530 Attributes attr = man.getAttributes(path); 531 String sealed = null; 532 if (attr != null) { 533 sealed = attr.getValue(Name.SEALED); 534 } 535 if (sealed == null) { 536 if ((attr = man.getMainAttributes()) != null) { 537 sealed = attr.getValue(Name.SEALED); 538 } 539 } 540 return "true".equalsIgnoreCase(sealed); 541 } 542 543 /** 544 * Finds the resource with the specified name on the URL search path. 545 * 546 * @param name the name of the resource 547 * @return a {@code URL} for the resource, or {@code null} 548 * if the resource could not be found, or if the loader is closed. 549 */ 550 public URL findResource(final String name) { 551 /* 552 * The same restriction to finding classes applies to resources 553 */ 554 URL url = AccessController.doPrivileged( 555 new PrivilegedAction<URL>() { 556 public URL run() { 557 return ucp.findResource(name, true); 558 } 559 }, acc); 560 561 return url != null ? ucp.checkURL(url) : null; 562 } 563 564 /** 565 * Returns an Enumeration of URLs representing all of the resources 566 * on the URL search path having the specified name. 567 * 568 * @param name the resource name 569 * @exception IOException if an I/O exception occurs 570 * @return an {@code Enumeration} of {@code URL}s 571 * If the loader is closed, the Enumeration will be empty. 572 */ 573 public Enumeration<URL> findResources(final String name) 574 throws IOException 575 { 576 final Enumeration<URL> e = ucp.findResources(name, true); 577 578 return new Enumeration<URL>() { 579 private URL url = null; 580 581 private boolean next() { 582 if (url != null) { 583 return true; 584 } 585 do { 586 URL u = AccessController.doPrivileged( 587 new PrivilegedAction<URL>() { 588 public URL run() { 589 if (!e.hasMoreElements()) 590 return null; 591 return e.nextElement(); 592 } 593 }, acc); 594 if (u == null) 595 break; 596 url = ucp.checkURL(u); 597 } while (url == null); 598 return url != null; 599 } 600 601 public URL nextElement() { 602 if (!next()) { 603 throw new NoSuchElementException(); 604 } 605 URL u = url; 606 url = null; 607 return u; 608 } 609 610 public boolean hasMoreElements() { 611 return next(); 612 } 613 }; 614 } 615 616 /** 617 * Returns the permissions for the given codesource object. 618 * The implementation of this method first calls super.getPermissions 619 * and then adds permissions based on the URL of the codesource. 620 * <p> 621 * If the protocol of this URL is "jar", then the permission granted 622 * is based on the permission that is required by the URL of the Jar 623 * file. 624 * <p> 625 * If the protocol is "file" and there is an authority component, then 626 * permission to connect to and accept connections from that authority 627 * may be granted. If the protocol is "file" 628 * and the path specifies a file, then permission to read that 629 * file is granted. If protocol is "file" and the path is 630 * a directory, permission is granted to read all files 631 * and (recursively) all files and subdirectories contained in 632 * that directory. 633 * <p> 634 * If the protocol is not "file", then permission 635 * to connect to and accept connections from the URL's host is granted. 636 * @param codesource the codesource 637 * @exception NullPointerException if {@code codesource} is {@code null}. 638 * @return the permissions granted to the codesource 639 */ 640 protected PermissionCollection getPermissions(CodeSource codesource) 641 { 642 PermissionCollection perms = super.getPermissions(codesource); 643 644 URL url = codesource.getLocation(); 645 646 Permission p; 647 URLConnection urlConnection; 648 649 try { 650 urlConnection = url.openConnection(); 651 p = urlConnection.getPermission(); 652 } catch (java.io.IOException ioe) { 653 p = null; 654 urlConnection = null; 655 } 656 657 if (p instanceof FilePermission) { 658 // if the permission has a separator char on the end, 659 // it means the codebase is a directory, and we need 660 // to add an additional permission to read recursively 661 String path = p.getName(); 662 if (path.endsWith(File.separator)) { 663 path += "-"; 664 p = new FilePermission(path, SecurityConstants.FILE_READ_ACTION); 665 } 666 } else if ((p == null) && (url.getProtocol().equals("file"))) { 667 String path = url.getFile().replace('/', File.separatorChar); 668 path = ParseUtil.decode(path); 669 if (path.endsWith(File.separator)) 670 path += "-"; 671 p = new FilePermission(path, SecurityConstants.FILE_READ_ACTION); 672 } else { 673 /** 674 * Not loading from a 'file:' URL so we want to give the class 675 * permission to connect to and accept from the remote host 676 * after we've made sure the host is the correct one and is valid. 677 */ 678 URL locUrl = url; 679 if (urlConnection instanceof JarURLConnection) { 680 locUrl = ((JarURLConnection)urlConnection).getJarFileURL(); 681 } 682 String host = locUrl.getHost(); 683 if (host != null && (host.length() > 0)) 684 p = new SocketPermission(host, 685 SecurityConstants.SOCKET_CONNECT_ACCEPT_ACTION); 686 } 687 688 // make sure the person that created this class loader 689 // would have this permission 690 691 if (p != null) { 692 final SecurityManager sm = System.getSecurityManager(); 693 if (sm != null) { 694 final Permission fp = p; 695 AccessController.doPrivileged(new PrivilegedAction<Void>() { 696 public Void run() throws SecurityException { 697 sm.checkPermission(fp); 698 return null; 699 } 700 }, acc); 701 } 702 perms.add(p); 703 } 704 return perms; 705 } 706 707 /** 708 * Creates a new instance of URLClassLoader for the specified 709 * URLs and parent class loader. If a security manager is 710 * installed, the {@code loadClass} method of the URLClassLoader 711 * returned by this method will invoke the 712 * {@code SecurityManager.checkPackageAccess} method before 713 * loading the class. 714 * 715 * @param urls the URLs to search for classes and resources 716 * @param parent the parent class loader for delegation 717 * @exception NullPointerException if {@code urls} is {@code null}. 718 * @return the resulting class loader 719 */ 720 public static URLClassLoader newInstance(final URL[] urls, 721 final ClassLoader parent) { 722 // Save the caller's context 723 final AccessControlContext acc = AccessController.getContext(); 724 // Need a privileged block to create the class loader 725 URLClassLoader ucl = AccessController.doPrivileged( 726 new PrivilegedAction<URLClassLoader>() { 727 public URLClassLoader run() { 728 return new FactoryURLClassLoader(urls, parent, acc); 729 } 730 }); 731 return ucl; 732 } 733 734 /** 735 * Creates a new instance of URLClassLoader for the specified 736 * URLs and default parent class loader. If a security manager is 737 * installed, the {@code loadClass} method of the URLClassLoader 738 * returned by this method will invoke the 739 * {@code SecurityManager.checkPackageAccess} before 740 * loading the class. 741 * 742 * @param urls the URLs to search for classes and resources 743 * @exception NullPointerException if {@code urls} is {@code null}. 744 * @return the resulting class loader 745 */ 746 public static URLClassLoader newInstance(final URL[] urls) { 747 // Save the caller's context 748 final AccessControlContext acc = AccessController.getContext(); 749 // Need a privileged block to create the class loader 750 URLClassLoader ucl = AccessController.doPrivileged( 751 new PrivilegedAction<URLClassLoader>() { 752 public URLClassLoader run() { 753 return new FactoryURLClassLoader(urls, acc); 754 } 755 }); 756 return ucl; 757 } 758 759 static { 760 sun.misc.SharedSecrets.setJavaNetAccess ( 761 new sun.misc.JavaNetAccess() { 762 public URLClassPath getURLClassPath (URLClassLoader u) { 763 return u.ucp; 764 } 765 } 766 ); 767 ClassLoader.registerAsParallelCapable(); 768 } 769 } 770 771 final class FactoryURLClassLoader extends URLClassLoader { 772 773 static { 774 ClassLoader.registerAsParallelCapable(); 775 } 776 777 FactoryURLClassLoader(URL[] urls, ClassLoader parent, 778 AccessControlContext acc) { 779 super(urls, parent, acc); 780 } 781 782 FactoryURLClassLoader(URL[] urls, AccessControlContext acc) { 783 super(urls, acc); 784 } 785 786 public final Class<?> loadClass(String name, boolean resolve) 787 throws ClassNotFoundException 788 { 789 // First check if we have permission to access the package. This 790 // should go away once we've added support for exported packages. 791 SecurityManager sm = System.getSecurityManager(); 792 if (sm != null) { 793 int i = name.lastIndexOf('.'); 794 if (i != -1) { 795 sm.checkPackageAccess(name.substring(0, i)); 796 } 797 } 798 return super.loadClass(name, resolve); 799 } 800 }