ZygoteInit.java revision 46703b099516c383a6882815bcf9cd4df0ec538d
1/* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package com.android.internal.os; 18 19import android.content.pm.ActivityInfo; 20import android.content.res.Resources; 21import android.content.res.TypedArray; 22import android.graphics.drawable.Drawable; 23import android.net.LocalServerSocket; 24import android.os.Debug; 25import android.os.FileUtils; 26import android.os.SystemClock; 27import android.os.SystemProperties; 28import android.util.Config; 29import android.util.EventLog; 30import android.util.Log; 31 32import dalvik.system.VMRuntime; 33import dalvik.system.Zygote; 34 35import libcore.io.IoUtils; 36 37import java.io.BufferedReader; 38import java.io.FileDescriptor; 39import java.io.IOException; 40import java.io.InputStream; 41import java.io.InputStreamReader; 42import java.lang.reflect.InvocationTargetException; 43import java.lang.reflect.Method; 44import java.lang.reflect.Modifier; 45import java.util.ArrayList; 46 47/** 48 * Startup class for the zygote process. 49 * 50 * Pre-initializes some classes, and then waits for commands on a UNIX domain 51 * socket. Based on these commands, forks of child processes that inherit 52 * the initial state of the VM. 53 * 54 * Please see {@link ZygoteConnection.Arguments} for documentation on the 55 * client protocol. 56 * 57 * @hide 58 */ 59public class ZygoteInit { 60 61 private static final String TAG = "Zygote"; 62 63 private static final String ANDROID_SOCKET_ENV = "ANDROID_SOCKET_zygote"; 64 65 private static final int LOG_BOOT_PROGRESS_PRELOAD_START = 3020; 66 private static final int LOG_BOOT_PROGRESS_PRELOAD_END = 3030; 67 68 /** when preloading, GC after allocating this many bytes */ 69 private static final int PRELOAD_GC_THRESHOLD = 50000; 70 71 public static final String USAGE_STRING = 72 " <\"true\"|\"false\" for startSystemServer>"; 73 74 private static LocalServerSocket sServerSocket; 75 76 /** 77 * Used to pre-load resources. We hold a global reference on it so it 78 * never gets destroyed. 79 */ 80 private static Resources mResources; 81 82 /** 83 * The number of times that the main Zygote loop 84 * should run before calling gc() again. 85 */ 86 static final int GC_LOOP_COUNT = 10; 87 88 /** 89 * If true, zygote forks for each peer. If false, a select loop is used 90 * inside a single process. The latter is preferred. 91 */ 92 private static final boolean ZYGOTE_FORK_MODE = false; 93 94 /** 95 * The name of a resource file that contains classes to preload. 96 */ 97 private static final String PRELOADED_CLASSES = "preloaded-classes"; 98 99 /** Controls whether we should preload resources during zygote init. */ 100 private static final boolean PRELOAD_RESOURCES = true; 101 102 /** 103 * Invokes a static "main(argv[]) method on class "className". 104 * Converts various failing exceptions into RuntimeExceptions, with 105 * the assumption that they will then cause the VM instance to exit. 106 * 107 * @param loader class loader to use 108 * @param className Fully-qualified class name 109 * @param argv Argument vector for main() 110 */ 111 static void invokeStaticMain(ClassLoader loader, 112 String className, String[] argv) 113 throws ZygoteInit.MethodAndArgsCaller { 114 Class<?> cl; 115 116 try { 117 cl = loader.loadClass(className); 118 } catch (ClassNotFoundException ex) { 119 throw new RuntimeException( 120 "Missing class when invoking static main " + className, 121 ex); 122 } 123 124 Method m; 125 try { 126 m = cl.getMethod("main", new Class[] { String[].class }); 127 } catch (NoSuchMethodException ex) { 128 throw new RuntimeException( 129 "Missing static main on " + className, ex); 130 } catch (SecurityException ex) { 131 throw new RuntimeException( 132 "Problem getting static main on " + className, ex); 133 } 134 135 int modifiers = m.getModifiers(); 136 if (! (Modifier.isStatic(modifiers) && Modifier.isPublic(modifiers))) { 137 throw new RuntimeException( 138 "Main method is not public and static on " + className); 139 } 140 141 /* 142 * This throw gets caught in ZygoteInit.main(), which responds 143 * by invoking the exception's run() method. This arrangement 144 * clears up all the stack frames that were required in setting 145 * up the process. 146 */ 147 throw new ZygoteInit.MethodAndArgsCaller(m, argv); 148 } 149 150 /** 151 * Registers a server socket for zygote command connections 152 * 153 * @throws RuntimeException when open fails 154 */ 155 private static void registerZygoteSocket() { 156 if (sServerSocket == null) { 157 int fileDesc; 158 try { 159 String env = System.getenv(ANDROID_SOCKET_ENV); 160 fileDesc = Integer.parseInt(env); 161 } catch (RuntimeException ex) { 162 throw new RuntimeException( 163 ANDROID_SOCKET_ENV + " unset or invalid", ex); 164 } 165 166 try { 167 sServerSocket = new LocalServerSocket( 168 createFileDescriptor(fileDesc)); 169 } catch (IOException ex) { 170 throw new RuntimeException( 171 "Error binding to local socket '" + fileDesc + "'", ex); 172 } 173 } 174 } 175 176 /** 177 * Waits for and accepts a single command connection. Throws 178 * RuntimeException on failure. 179 */ 180 private static ZygoteConnection acceptCommandPeer() { 181 try { 182 return new ZygoteConnection(sServerSocket.accept()); 183 } catch (IOException ex) { 184 throw new RuntimeException( 185 "IOException during accept()", ex); 186 } 187 } 188 189 /** 190 * Close and clean up zygote sockets. Called on shutdown and on the 191 * child's exit path. 192 */ 193 static void closeServerSocket() { 194 try { 195 if (sServerSocket != null) { 196 sServerSocket.close(); 197 } 198 } catch (IOException ex) { 199 Log.e(TAG, "Zygote: error closing sockets", ex); 200 } 201 202 sServerSocket = null; 203 } 204 205 private static final int UNPRIVILEGED_UID = 9999; 206 private static final int UNPRIVILEGED_GID = 9999; 207 208 private static final int ROOT_UID = 0; 209 private static final int ROOT_GID = 0; 210 211 /** 212 * Sets effective user ID. 213 */ 214 private static void setEffectiveUser(int uid) { 215 int errno = setreuid(ROOT_UID, uid); 216 if (errno != 0) { 217 Log.e(TAG, "setreuid() failed. errno: " + errno); 218 } 219 } 220 221 /** 222 * Sets effective group ID. 223 */ 224 private static void setEffectiveGroup(int gid) { 225 int errno = setregid(ROOT_GID, gid); 226 if (errno != 0) { 227 Log.e(TAG, "setregid() failed. errno: " + errno); 228 } 229 } 230 231 /** 232 * Performs Zygote process initialization. Loads and initializes 233 * commonly used classes. 234 * 235 * Most classes only cause a few hundred bytes to be allocated, but 236 * a few will allocate a dozen Kbytes (in one case, 500+K). 237 */ 238 private static void preloadClasses() { 239 final VMRuntime runtime = VMRuntime.getRuntime(); 240 241 InputStream is = ZygoteInit.class.getClassLoader().getResourceAsStream( 242 PRELOADED_CLASSES); 243 if (is == null) { 244 Log.e(TAG, "Couldn't find " + PRELOADED_CLASSES + "."); 245 } else { 246 Log.i(TAG, "Preloading classes..."); 247 long startTime = SystemClock.uptimeMillis(); 248 249 // Drop root perms while running static initializers. 250 setEffectiveGroup(UNPRIVILEGED_GID); 251 setEffectiveUser(UNPRIVILEGED_UID); 252 253 // Alter the target heap utilization. With explicit GCs this 254 // is not likely to have any effect. 255 float defaultUtilization = runtime.getTargetHeapUtilization(); 256 runtime.setTargetHeapUtilization(0.8f); 257 258 // Start with a clean slate. 259 System.gc(); 260 runtime.runFinalizationSync(); 261 Debug.startAllocCounting(); 262 263 try { 264 BufferedReader br 265 = new BufferedReader(new InputStreamReader(is), 256); 266 267 int count = 0; 268 String line; 269 while ((line = br.readLine()) != null) { 270 // Skip comments and blank lines. 271 line = line.trim(); 272 if (line.startsWith("#") || line.equals("")) { 273 continue; 274 } 275 276 try { 277 if (Config.LOGV) { 278 Log.v(TAG, "Preloading " + line + "..."); 279 } 280 Class.forName(line); 281 if (Debug.getGlobalAllocSize() > PRELOAD_GC_THRESHOLD) { 282 if (Config.LOGV) { 283 Log.v(TAG, 284 " GC at " + Debug.getGlobalAllocSize()); 285 } 286 System.gc(); 287 runtime.runFinalizationSync(); 288 Debug.resetGlobalAllocSize(); 289 } 290 count++; 291 } catch (ClassNotFoundException e) { 292 Log.w(TAG, "Class not found for preloading: " + line); 293 } catch (Throwable t) { 294 Log.e(TAG, "Error preloading " + line + ".", t); 295 if (t instanceof Error) { 296 throw (Error) t; 297 } 298 if (t instanceof RuntimeException) { 299 throw (RuntimeException) t; 300 } 301 throw new RuntimeException(t); 302 } 303 } 304 305 Log.i(TAG, "...preloaded " + count + " classes in " 306 + (SystemClock.uptimeMillis()-startTime) + "ms."); 307 } catch (IOException e) { 308 Log.e(TAG, "Error reading " + PRELOADED_CLASSES + ".", e); 309 } finally { 310 IoUtils.closeQuietly(is); 311 // Restore default. 312 runtime.setTargetHeapUtilization(defaultUtilization); 313 314 Debug.stopAllocCounting(); 315 316 // Bring back root. We'll need it later. 317 setEffectiveUser(ROOT_UID); 318 setEffectiveGroup(ROOT_GID); 319 } 320 } 321 } 322 323 /** 324 * Load in commonly used resources, so they can be shared across 325 * processes. 326 * 327 * These tend to be a few Kbytes, but are frequently in the 20-40K 328 * range, and occasionally even larger. 329 */ 330 private static void preloadResources() { 331 final VMRuntime runtime = VMRuntime.getRuntime(); 332 333 Debug.startAllocCounting(); 334 try { 335 System.gc(); 336 runtime.runFinalizationSync(); 337 mResources = Resources.getSystem(); 338 mResources.startPreloading(); 339 if (PRELOAD_RESOURCES) { 340 Log.i(TAG, "Preloading resources..."); 341 342 long startTime = SystemClock.uptimeMillis(); 343 TypedArray ar = mResources.obtainTypedArray( 344 com.android.internal.R.array.preloaded_drawables); 345 int N = preloadDrawables(runtime, ar); 346 Log.i(TAG, "...preloaded " + N + " resources in " 347 + (SystemClock.uptimeMillis()-startTime) + "ms."); 348 349 startTime = SystemClock.uptimeMillis(); 350 ar = mResources.obtainTypedArray( 351 com.android.internal.R.array.preloaded_color_state_lists); 352 N = preloadColorStateLists(runtime, ar); 353 Log.i(TAG, "...preloaded " + N + " resources in " 354 + (SystemClock.uptimeMillis()-startTime) + "ms."); 355 } 356 mResources.finishPreloading(); 357 } catch (RuntimeException e) { 358 Log.w(TAG, "Failure preloading resources", e); 359 } finally { 360 Debug.stopAllocCounting(); 361 } 362 } 363 364 private static int preloadColorStateLists(VMRuntime runtime, TypedArray ar) { 365 int N = ar.length(); 366 for (int i=0; i<N; i++) { 367 if (Debug.getGlobalAllocSize() > PRELOAD_GC_THRESHOLD) { 368 if (Config.LOGV) { 369 Log.v(TAG, " GC at " + Debug.getGlobalAllocSize()); 370 } 371 System.gc(); 372 runtime.runFinalizationSync(); 373 Debug.resetGlobalAllocSize(); 374 } 375 int id = ar.getResourceId(i, 0); 376 if (Config.LOGV) { 377 Log.v(TAG, "Preloading resource #" + Integer.toHexString(id)); 378 } 379 if (id != 0) { 380 mResources.getColorStateList(id); 381 } 382 } 383 return N; 384 } 385 386 387 private static int preloadDrawables(VMRuntime runtime, TypedArray ar) { 388 int N = ar.length(); 389 for (int i=0; i<N; i++) { 390 if (Debug.getGlobalAllocSize() > PRELOAD_GC_THRESHOLD) { 391 if (Config.LOGV) { 392 Log.v(TAG, " GC at " + Debug.getGlobalAllocSize()); 393 } 394 System.gc(); 395 runtime.runFinalizationSync(); 396 Debug.resetGlobalAllocSize(); 397 } 398 int id = ar.getResourceId(i, 0); 399 if (Config.LOGV) { 400 Log.v(TAG, "Preloading resource #" + Integer.toHexString(id)); 401 } 402 if (id != 0) { 403 Drawable dr = mResources.getDrawable(id); 404 if ((dr.getChangingConfigurations()&~ActivityInfo.CONFIG_FONT_SCALE) != 0) { 405 Log.w(TAG, "Preloaded drawable resource #0x" 406 + Integer.toHexString(id) 407 + " (" + ar.getString(i) + ") that varies with configuration!!"); 408 } 409 } 410 } 411 return N; 412 } 413 414 /** 415 * Runs several special GCs to try to clean up a few generations of 416 * softly- and final-reachable objects, along with any other garbage. 417 * This is only useful just before a fork(). 418 */ 419 /*package*/ static void gc() { 420 final VMRuntime runtime = VMRuntime.getRuntime(); 421 422 /* runFinalizationSync() lets finalizers be called in Zygote, 423 * which doesn't have a HeapWorker thread. 424 */ 425 System.gc(); 426 runtime.runFinalizationSync(); 427 System.gc(); 428 runtime.runFinalizationSync(); 429 System.gc(); 430 runtime.runFinalizationSync(); 431 } 432 433 /** 434 * Finish remaining work for the newly forked system server process. 435 */ 436 private static void handleSystemServerProcess( 437 ZygoteConnection.Arguments parsedArgs) 438 throws ZygoteInit.MethodAndArgsCaller { 439 440 closeServerSocket(); 441 442 // set umask to 0077 so new files and directories will default to owner-only permissions. 443 FileUtils.setUMask(FileUtils.S_IRWXG | FileUtils.S_IRWXO); 444 445 /* 446 * Pass the remaining arguments to SystemServer. 447 * "--nice-name=system_server com.android.server.SystemServer" 448 */ 449 RuntimeInit.zygoteInit(parsedArgs.remainingArgs); 450 /* should never reach here */ 451 } 452 453 /** 454 * Prepare the arguments and fork for the system server process. 455 */ 456 private static boolean startSystemServer() 457 throws MethodAndArgsCaller, RuntimeException { 458 /* Hardcoded command line to start the system server */ 459 String args[] = { 460 "--setuid=1000", 461 "--setgid=1000", 462 "--setgroups=1001,1002,1003,1004,1005,1006,1007,1008,1009,1010,1018,3001,3002,3003", 463 "--capabilities=130104352,130104352", 464 "--runtime-init", 465 "--nice-name=system_server", 466 "com.android.server.SystemServer", 467 }; 468 ZygoteConnection.Arguments parsedArgs = null; 469 470 int pid; 471 472 try { 473 parsedArgs = new ZygoteConnection.Arguments(args); 474 475 /* 476 * Enable debugging of the system process if *either* the command line flags 477 * indicate it should be debuggable or the ro.debuggable system property 478 * is set to "1" 479 */ 480 int debugFlags = parsedArgs.debugFlags; 481 if ("1".equals(SystemProperties.get("ro.debuggable"))) 482 debugFlags |= Zygote.DEBUG_ENABLE_DEBUGGER; 483 484 /* Request to fork the system server process */ 485 pid = Zygote.forkSystemServer( 486 parsedArgs.uid, parsedArgs.gid, 487 parsedArgs.gids, debugFlags, null, 488 parsedArgs.permittedCapabilities, 489 parsedArgs.effectiveCapabilities); 490 } catch (IllegalArgumentException ex) { 491 throw new RuntimeException(ex); 492 } 493 494 /* For child process */ 495 if (pid == 0) { 496 handleSystemServerProcess(parsedArgs); 497 } 498 499 return true; 500 } 501 502 public static void main(String argv[]) { 503 try { 504 // Start profiling the zygote initialization. 505 SamplingProfilerIntegration.start(); 506 507 registerZygoteSocket(); 508 EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_START, 509 SystemClock.uptimeMillis()); 510 preloadClasses(); 511 preloadResources(); 512 EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_END, 513 SystemClock.uptimeMillis()); 514 515 // Finish profiling the zygote initialization. 516 SamplingProfilerIntegration.writeZygoteSnapshot(); 517 518 // Do an initial gc to clean up after startup 519 gc(); 520 521 // If requested, start system server directly from Zygote 522 if (argv.length != 2) { 523 throw new RuntimeException(argv[0] + USAGE_STRING); 524 } 525 526 if (argv[1].equals("true")) { 527 startSystemServer(); 528 } else if (!argv[1].equals("false")) { 529 throw new RuntimeException(argv[0] + USAGE_STRING); 530 } 531 532 Log.i(TAG, "Accepting command socket connections"); 533 534 if (ZYGOTE_FORK_MODE) { 535 runForkMode(); 536 } else { 537 runSelectLoopMode(); 538 } 539 540 closeServerSocket(); 541 } catch (MethodAndArgsCaller caller) { 542 caller.run(); 543 } catch (RuntimeException ex) { 544 Log.e(TAG, "Zygote died with exception", ex); 545 closeServerSocket(); 546 throw ex; 547 } 548 } 549 550 /** 551 * Runs the zygote in accept-and-fork mode. In this mode, each peer 552 * gets its own zygote spawner process. This code is retained for 553 * reference only. 554 * 555 * @throws MethodAndArgsCaller in a child process when a main() should 556 * be executed. 557 */ 558 private static void runForkMode() throws MethodAndArgsCaller { 559 while (true) { 560 ZygoteConnection peer = acceptCommandPeer(); 561 562 int pid; 563 564 pid = Zygote.fork(); 565 566 if (pid == 0) { 567 // The child process should handle the peer requests 568 569 // The child does not accept any more connections 570 try { 571 sServerSocket.close(); 572 } catch (IOException ex) { 573 Log.e(TAG, "Zygote Child: error closing sockets", ex); 574 } finally { 575 sServerSocket = null; 576 } 577 578 peer.run(); 579 break; 580 } else if (pid > 0) { 581 peer.closeSocket(); 582 } else { 583 throw new RuntimeException("Error invoking fork()"); 584 } 585 } 586 } 587 588 /** 589 * Runs the zygote process's select loop. Accepts new connections as 590 * they happen, and reads commands from connections one spawn-request's 591 * worth at a time. 592 * 593 * @throws MethodAndArgsCaller in a child process when a main() should 594 * be executed. 595 */ 596 private static void runSelectLoopMode() throws MethodAndArgsCaller { 597 ArrayList<FileDescriptor> fds = new ArrayList(); 598 ArrayList<ZygoteConnection> peers = new ArrayList(); 599 FileDescriptor[] fdArray = new FileDescriptor[4]; 600 601 fds.add(sServerSocket.getFileDescriptor()); 602 peers.add(null); 603 604 int loopCount = GC_LOOP_COUNT; 605 while (true) { 606 int index; 607 608 /* 609 * Call gc() before we block in select(). 610 * It's work that has to be done anyway, and it's better 611 * to avoid making every child do it. It will also 612 * madvise() any free memory as a side-effect. 613 * 614 * Don't call it every time, because walking the entire 615 * heap is a lot of overhead to free a few hundred bytes. 616 */ 617 if (loopCount <= 0) { 618 gc(); 619 loopCount = GC_LOOP_COUNT; 620 } else { 621 loopCount--; 622 } 623 624 625 try { 626 fdArray = fds.toArray(fdArray); 627 index = selectReadable(fdArray); 628 } catch (IOException ex) { 629 throw new RuntimeException("Error in select()", ex); 630 } 631 632 if (index < 0) { 633 throw new RuntimeException("Error in select()"); 634 } else if (index == 0) { 635 ZygoteConnection newPeer = acceptCommandPeer(); 636 peers.add(newPeer); 637 fds.add(newPeer.getFileDesciptor()); 638 } else { 639 boolean done; 640 done = peers.get(index).runOnce(); 641 642 if (done) { 643 peers.remove(index); 644 fds.remove(index); 645 } 646 } 647 } 648 } 649 650 /** 651 * The Linux syscall "setreuid()" 652 * @param ruid real uid 653 * @param euid effective uid 654 * @return 0 on success, non-zero errno on fail 655 */ 656 static native int setreuid(int ruid, int euid); 657 658 /** 659 * The Linux syscall "setregid()" 660 * @param rgid real gid 661 * @param egid effective gid 662 * @return 0 on success, non-zero errno on fail 663 */ 664 static native int setregid(int rgid, int egid); 665 666 /** 667 * Invokes the linux syscall "setpgid" 668 * 669 * @param pid pid to change 670 * @param pgid new process group of pid 671 * @return 0 on success or non-zero errno on fail 672 */ 673 static native int setpgid(int pid, int pgid); 674 675 /** 676 * Invokes the linux syscall "getpgid" 677 * 678 * @param pid pid to query 679 * @return pgid of pid in question 680 * @throws IOException on error 681 */ 682 static native int getpgid(int pid) throws IOException; 683 684 /** 685 * Invokes the syscall dup2() to copy the specified descriptors into 686 * stdin, stdout, and stderr. The existing stdio descriptors will be 687 * closed and errors during close will be ignored. The specified 688 * descriptors will also remain open at their original descriptor numbers, 689 * so the caller may want to close the original descriptors. 690 * 691 * @param in new stdin 692 * @param out new stdout 693 * @param err new stderr 694 * @throws IOException 695 */ 696 static native void reopenStdio(FileDescriptor in, 697 FileDescriptor out, FileDescriptor err) throws IOException; 698 699 /** 700 * Calls close() on a file descriptor 701 * 702 * @param fd descriptor to close 703 * @throws IOException 704 */ 705 static native void closeDescriptor(FileDescriptor fd) 706 throws IOException; 707 708 /** 709 * Toggles the close-on-exec flag for the specified file descriptor. 710 * 711 * @param fd non-null; file descriptor 712 * @param flag desired close-on-exec flag state 713 * @throws IOException 714 */ 715 static native void setCloseOnExec(FileDescriptor fd, boolean flag) 716 throws IOException; 717 718 /** 719 * Retrieves the permitted capability set from another process. 720 * 721 * @param pid >=0 process ID or 0 for this process 722 * @throws IOException on error 723 */ 724 static native long capgetPermitted(int pid) 725 throws IOException; 726 727 /** 728 * Sets the permitted and effective capability sets of this process. 729 * 730 * @param permittedCapabilities permitted set 731 * @param effectiveCapabilities effective set 732 * @throws IOException on error 733 */ 734 static native void setCapabilities( 735 long permittedCapabilities, 736 long effectiveCapabilities) throws IOException; 737 738 /** 739 * Invokes select() on the provider array of file descriptors (selecting 740 * for readability only). Array elements of null are ignored. 741 * 742 * @param fds non-null; array of readable file descriptors 743 * @return index of descriptor that is now readable or -1 for empty array. 744 * @throws IOException if an error occurs 745 */ 746 static native int selectReadable(FileDescriptor[] fds) throws IOException; 747 748 /** 749 * Creates a file descriptor from an int fd. 750 * 751 * @param fd integer OS file descriptor 752 * @return non-null; FileDescriptor instance 753 * @throws IOException if fd is invalid 754 */ 755 static native FileDescriptor createFileDescriptor(int fd) 756 throws IOException; 757 758 /** 759 * Class not instantiable. 760 */ 761 private ZygoteInit() { 762 } 763 764 /** 765 * Helper exception class which holds a method and arguments and 766 * can call them. This is used as part of a trampoline to get rid of 767 * the initial process setup stack frames. 768 */ 769 public static class MethodAndArgsCaller extends Exception 770 implements Runnable { 771 /** method to call */ 772 private final Method mMethod; 773 774 /** argument array */ 775 private final String[] mArgs; 776 777 public MethodAndArgsCaller(Method method, String[] args) { 778 mMethod = method; 779 mArgs = args; 780 } 781 782 public void run() { 783 try { 784 mMethod.invoke(null, new Object[] { mArgs }); 785 } catch (IllegalAccessException ex) { 786 throw new RuntimeException(ex); 787 } catch (InvocationTargetException ex) { 788 Throwable cause = ex.getCause(); 789 if (cause instanceof RuntimeException) { 790 throw (RuntimeException) cause; 791 } else if (cause instanceof Error) { 792 throw (Error) cause; 793 } 794 throw new RuntimeException(ex); 795 } 796 } 797 } 798} 799