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1: /* Runtime.java -- access to the VM process 2: Copyright (C) 1998, 2002, 2003, 2004, 2005, 2006 Free Software Foundation 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package java.lang; 40: 41: import gnu.classpath.SystemProperties; 42: 43: import java.io.File; 44: import java.io.IOException; 45: import java.io.InputStream; 46: import java.io.OutputStream; 47: import java.util.HashSet; 48: import java.util.Iterator; 49: import java.util.Set; 50: import java.util.StringTokenizer; 51: 52: /** 53: * Runtime represents the Virtual Machine. 54: * 55: * @author John Keiser 56: * @author Eric Blake (ebb9@email.byu.edu) 57: * @author Jeroen Frijters 58: */ 59: // No idea why this class isn't final, since you can't build a subclass! 60: public class Runtime 61: { 62: /** 63: * The library path, to search when loading libraries. We can also safely use 64: * this as a lock for synchronization. 65: */ 66: private final String[] libpath; 67: 68: static 69: { 70: init(); 71: } 72: 73: /** 74: * The thread that started the exit sequence. Access to this field must 75: * be thread-safe; lock on libpath to avoid deadlock with user code. 76: * <code>runFinalization()</code> may want to look at this to see if ALL 77: * finalizers should be run, because the virtual machine is about to halt. 78: */ 79: private Thread exitSequence; 80: 81: /** 82: * All shutdown hooks. This is initialized lazily, and set to null once all 83: * shutdown hooks have run. Access to this field must be thread-safe; lock 84: * on libpath to avoid deadlock with user code. 85: */ 86: private Set shutdownHooks; 87: 88: /** True if we should finalize on exit. */ 89: private boolean finalizeOnExit; 90: 91: /** 92: * The one and only runtime instance. 93: */ 94: private static final Runtime current = new Runtime(); 95: 96: /** 97: * Not instantiable by a user, this should only create one instance. 98: */ 99: private Runtime() 100: { 101: if (current != null) 102: throw new InternalError("Attempt to recreate Runtime"); 103: 104: // We don't use libpath in the libgcj implementation. We still 105: // set it to something to allow the various synchronizations to 106: // work. 107: libpath = new String[0]; 108: } 109: 110: /** 111: * Get the current Runtime object for this JVM. This is necessary to access 112: * the many instance methods of this class. 113: * 114: * @return the current Runtime object 115: */ 116: public static Runtime getRuntime() 117: { 118: return current; 119: } 120: 121: /** 122: * Exit the Java runtime. This method will either throw a SecurityException 123: * or it will never return. The status code is returned to the system; often 124: * a non-zero status code indicates an abnormal exit. Of course, there is a 125: * security check, <code>checkExit(status)</code>. 126: * 127: * <p>First, all shutdown hooks are run, in unspecified order, and 128: * concurrently. Next, if finalization on exit has been enabled, all pending 129: * finalizers are run. Finally, the system calls <code>halt</code>.</p> 130: * 131: * <p>If this is run a second time after shutdown has already started, there 132: * are two actions. If shutdown hooks are still executing, it blocks 133: * indefinitely. Otherwise, if the status is nonzero it halts immediately; 134: * if it is zero, it blocks indefinitely. This is typically called by 135: * <code>System.exit</code>.</p> 136: * 137: * @param status the status to exit with 138: * @throws SecurityException if permission is denied 139: * @see #addShutdownHook(Thread) 140: * @see #runFinalizersOnExit(boolean) 141: * @see #runFinalization() 142: * @see #halt(int) 143: */ 144: public void exit(int status) 145: { 146: SecurityManager sm = SecurityManager.current; // Be thread-safe! 147: if (sm != null) 148: sm.checkExit(status); 149: exitNoChecks(status); 150: } 151: 152: // Accessor to avoid adding a vtable slot. 153: static void exitNoChecksAccessor(int status) 154: { 155: current.exitNoChecks(status); 156: } 157: 158: // Private since we can't add a vtable slot in 4.1.x. 159: private void exitNoChecks(int status) 160: { 161: if (runShutdownHooks()) 162: exitInternal(status); 163: 164: // Someone else already called runShutdownHooks(). 165: // Make sure we are not/no longer in the shutdownHooks set. 166: // And wait till the thread that is calling runShutdownHooks() finishes. 167: synchronized (libpath) 168: { 169: if (shutdownHooks != null) 170: { 171: shutdownHooks.remove(Thread.currentThread()); 172: // Interrupt the exit sequence thread, in case it was waiting 173: // inside a join on our thread. 174: exitSequence.interrupt(); 175: // Shutdown hooks are still running, so we clear status to 176: // make sure we don't halt. 177: status = 0; 178: } 179: } 180: 181: // If exit() is called again after the shutdown hooks have run, but 182: // while finalization for exit is going on and the status is non-zero 183: // we halt immediately. 184: if (status != 0) 185: exitInternal(status); 186: 187: while (true) 188: try 189: { 190: exitSequence.join(); 191: } 192: catch (InterruptedException e) 193: { 194: // Ignore, we've suspended indefinitely to let all shutdown 195: // hooks complete, and to let any non-zero exits through, because 196: // this is a duplicate call to exit(0). 197: } 198: } 199: 200: /** 201: * On first invocation, run all the shutdown hooks and return true. 202: * Any subsequent invocations will simply return false. 203: * Note that it is package accessible so that VMRuntime can call it 204: * when VM exit is not triggered by a call to Runtime.exit(). 205: * 206: * @return was the current thread the first one to call this method? 207: */ 208: boolean runShutdownHooks() 209: { 210: boolean first = false; 211: synchronized (libpath) // Synch on libpath, not this, to avoid deadlock. 212: { 213: if (exitSequence == null) 214: { 215: first = true; 216: exitSequence = Thread.currentThread(); 217: if (shutdownHooks != null) 218: { 219: Iterator i = shutdownHooks.iterator(); 220: while (i.hasNext()) // Start all shutdown hooks. 221: try 222: { 223: ((Thread) i.next()).start(); 224: } 225: catch (IllegalThreadStateException e) 226: { 227: i.remove(); 228: } 229: } 230: } 231: } 232: if (first) 233: { 234: if (shutdownHooks != null) 235: { 236: // Check progress of all shutdown hooks. As a hook completes, 237: // remove it from the set. If a hook calls exit, it removes 238: // itself from the set, then waits indefinitely on the 239: // exitSequence thread. Once the set is empty, set it to null to 240: // signal all finalizer threads that halt may be called. 241: while (true) 242: { 243: Thread[] hooks; 244: synchronized (libpath) 245: { 246: hooks = new Thread[shutdownHooks.size()]; 247: shutdownHooks.toArray(hooks); 248: } 249: if (hooks.length == 0) 250: break; 251: for (int i = 0; i < hooks.length; i++) 252: { 253: try 254: { 255: synchronized (libpath) 256: { 257: if (!shutdownHooks.contains(hooks[i])) 258: continue; 259: } 260: hooks[i].join(); 261: synchronized (libpath) 262: { 263: shutdownHooks.remove(hooks[i]); 264: } 265: } 266: catch (InterruptedException x) 267: { 268: // continue waiting on the next thread 269: } 270: } 271: } 272: synchronized (libpath) 273: { 274: shutdownHooks = null; 275: } 276: } 277: // Run finalization on all finalizable objects (even if they are 278: // still reachable). 279: runFinalizationForExit(); 280: } 281: return first; 282: } 283: 284: /** 285: * Register a new shutdown hook. This is invoked when the program exits 286: * normally (because all non-daemon threads ended, or because 287: * <code>System.exit</code> was invoked), or when the user terminates 288: * the virtual machine (such as by typing ^C, or logging off). There is 289: * a security check to add hooks, 290: * <code>RuntimePermission("shutdownHooks")</code>. 291: * 292: * <p>The hook must be an initialized, but unstarted Thread. The threads 293: * are run concurrently, and started in an arbitrary order; and user 294: * threads or daemons may still be running. Once shutdown hooks have 295: * started, they must all complete, or else you must use <code>halt</code>, 296: * to actually finish the shutdown sequence. Attempts to modify hooks 297: * after shutdown has started result in IllegalStateExceptions.</p> 298: * 299: * <p>It is imperative that you code shutdown hooks defensively, as you 300: * do not want to deadlock, and have no idea what other hooks will be 301: * running concurrently. It is also a good idea to finish quickly, as the 302: * virtual machine really wants to shut down!</p> 303: * 304: * <p>There are no guarantees that such hooks will run, as there are ways 305: * to forcibly kill a process. But in such a drastic case, shutdown hooks 306: * would do little for you in the first place.</p> 307: * 308: * @param hook an initialized, unstarted Thread 309: * @throws IllegalArgumentException if the hook is already registered or run 310: * @throws IllegalStateException if the virtual machine is already in 311: * the shutdown sequence 312: * @throws SecurityException if permission is denied 313: * @since 1.3 314: * @see #removeShutdownHook(Thread) 315: * @see #exit(int) 316: * @see #halt(int) 317: */ 318: public void addShutdownHook(Thread hook) 319: { 320: SecurityManager sm = SecurityManager.current; // Be thread-safe! 321: if (sm != null) 322: sm.checkPermission(new RuntimePermission("shutdownHooks")); 323: if (hook.isAlive() || hook.getThreadGroup() == null) 324: throw new IllegalArgumentException("The hook thread " + hook + " must not have been already run or started"); 325: synchronized (libpath) 326: { 327: if (exitSequence != null) 328: throw new IllegalStateException("The Virtual Machine is exiting. It is not possible anymore to add any hooks"); 329: if (shutdownHooks == null) 330: shutdownHooks = new HashSet(); // Lazy initialization. 331: if (! shutdownHooks.add(hook)) 332: throw new IllegalArgumentException(hook.toString() + " had already been inserted"); 333: } 334: } 335: 336: /** 337: * De-register a shutdown hook. As when you registered it, there is a 338: * security check to remove hooks, 339: * <code>RuntimePermission("shutdownHooks")</code>. 340: * 341: * @param hook the hook to remove 342: * @return true if the hook was successfully removed, false if it was not 343: * registered in the first place 344: * @throws IllegalStateException if the virtual machine is already in 345: * the shutdown sequence 346: * @throws SecurityException if permission is denied 347: * @since 1.3 348: * @see #addShutdownHook(Thread) 349: * @see #exit(int) 350: * @see #halt(int) 351: */ 352: public boolean removeShutdownHook(Thread hook) 353: { 354: SecurityManager sm = SecurityManager.current; // Be thread-safe! 355: if (sm != null) 356: sm.checkPermission(new RuntimePermission("shutdownHooks")); 357: synchronized (libpath) 358: { 359: if (exitSequence != null) 360: throw new IllegalStateException(); 361: if (shutdownHooks != null) 362: return shutdownHooks.remove(hook); 363: } 364: return false; 365: } 366: 367: /** 368: * Forcibly terminate the virtual machine. This call never returns. It is 369: * much more severe than <code>exit</code>, as it bypasses all shutdown 370: * hooks and initializers. Use caution in calling this! Of course, there is 371: * a security check, <code>checkExit(status)</code>. 372: * 373: * @param status the status to exit with 374: * @throws SecurityException if permission is denied 375: * @since 1.3 376: * @see #exit(int) 377: * @see #addShutdownHook(Thread) 378: */ 379: public void halt(int status) 380: { 381: SecurityManager sm = SecurityManager.current; // Be thread-safe! 382: if (sm != null) 383: sm.checkExit(status); 384: exitInternal(status); 385: } 386: 387: /** 388: * Tell the VM to run the finalize() method on every single Object before 389: * it exits. Note that the JVM may still exit abnormally and not perform 390: * this, so you still don't have a guarantee. And besides that, this is 391: * inherently unsafe in multi-threaded code, as it may result in deadlock 392: * as multiple threads compete to manipulate objects. This value defaults to 393: * <code>false</code>. There is a security check, <code>checkExit(0)</code>. 394: * 395: * @param finalizeOnExit whether to finalize all Objects on exit 396: * @throws SecurityException if permission is denied 397: * @see #exit(int) 398: * @see #gc() 399: * @since 1.1 400: * @deprecated never rely on finalizers to do a clean, thread-safe, 401: * mop-up from your code 402: */ 403: public static void runFinalizersOnExit(boolean finalizeOnExit) 404: { 405: SecurityManager sm = SecurityManager.current; // Be thread-safe! 406: if (sm != null) 407: sm.checkExit(0); 408: current.finalizeOnExit = finalizeOnExit; 409: } 410: 411: /** 412: * Create a new subprocess with the specified command line. Calls 413: * <code>exec(cmdline, null, null)</code>. A security check is performed, 414: * <code>checkExec</code>. 415: * 416: * @param cmdline the command to call 417: * @return the Process object 418: * @throws SecurityException if permission is denied 419: * @throws IOException if an I/O error occurs 420: * @throws NullPointerException if cmdline is null 421: * @throws IndexOutOfBoundsException if cmdline is "" 422: */ 423: public Process exec(String cmdline) throws IOException 424: { 425: return exec(cmdline, null, null); 426: } 427: 428: /** 429: * Create a new subprocess with the specified command line and environment. 430: * If the environment is null, the process inherits the environment of 431: * this process. Calls <code>exec(cmdline, env, null)</code>. A security 432: * check is performed, <code>checkExec</code>. 433: * 434: * @param cmdline the command to call 435: * @param env the environment to use, in the format name=value 436: * @return the Process object 437: * @throws SecurityException if permission is denied 438: * @throws IOException if an I/O error occurs 439: * @throws NullPointerException if cmdline is null, or env has null entries 440: * @throws IndexOutOfBoundsException if cmdline is "" 441: */ 442: public Process exec(String cmdline, String[] env) throws IOException 443: { 444: return exec(cmdline, env, null); 445: } 446: 447: /** 448: * Create a new subprocess with the specified command line, environment, and 449: * working directory. If the environment is null, the process inherits the 450: * environment of this process. If the directory is null, the process uses 451: * the current working directory. This splits cmdline into an array, using 452: * the default StringTokenizer, then calls 453: * <code>exec(cmdArray, env, dir)</code>. A security check is performed, 454: * <code>checkExec</code>. 455: * 456: * @param cmdline the command to call 457: * @param env the environment to use, in the format name=value 458: * @param dir the working directory to use 459: * @return the Process object 460: * @throws SecurityException if permission is denied 461: * @throws IOException if an I/O error occurs 462: * @throws NullPointerException if cmdline is null, or env has null entries 463: * @throws IndexOutOfBoundsException if cmdline is "" 464: * @since 1.3 465: */ 466: public Process exec(String cmdline, String[] env, File dir) 467: throws IOException 468: { 469: StringTokenizer t = new StringTokenizer(cmdline); 470: String[] cmd = new String[t.countTokens()]; 471: for (int i = 0; i < cmd.length; i++) 472: cmd[i] = t.nextToken(); 473: return exec(cmd, env, dir); 474: } 475: 476: /** 477: * Create a new subprocess with the specified command line, already 478: * tokenized. Calls <code>exec(cmd, null, null)</code>. A security check 479: * is performed, <code>checkExec</code>. 480: * 481: * @param cmd the command to call 482: * @return the Process object 483: * @throws SecurityException if permission is denied 484: * @throws IOException if an I/O error occurs 485: * @throws NullPointerException if cmd is null, or has null entries 486: * @throws IndexOutOfBoundsException if cmd is length 0 487: */ 488: public Process exec(String[] cmd) throws IOException 489: { 490: return exec(cmd, null, null); 491: } 492: 493: /** 494: * Create a new subprocess with the specified command line, already 495: * tokenized, and specified environment. If the environment is null, the 496: * process inherits the environment of this process. Calls 497: * <code>exec(cmd, env, null)</code>. A security check is performed, 498: * <code>checkExec</code>. 499: * 500: * @param cmd the command to call 501: * @param env the environment to use, in the format name=value 502: * @return the Process object 503: * @throws SecurityException if permission is denied 504: * @throws IOException if an I/O error occurs 505: * @throws NullPointerException if cmd is null, or cmd or env has null 506: * entries 507: * @throws IndexOutOfBoundsException if cmd is length 0 508: */ 509: public Process exec(String[] cmd, String[] env) throws IOException 510: { 511: return exec(cmd, env, null); 512: } 513: 514: /** 515: * Create a new subprocess with the specified command line, already 516: * tokenized, and the specified environment and working directory. If the 517: * environment is null, the process inherits the environment of this 518: * process. If the directory is null, the process uses the current working 519: * directory. A security check is performed, <code>checkExec</code>. 520: * 521: * @param cmd the command to call 522: * @param env the environment to use, in the format name=value 523: * @param dir the working directory to use 524: * @return the Process object 525: * @throws SecurityException if permission is denied 526: * @throws IOException if an I/O error occurs 527: * @throws NullPointerException if cmd is null, or cmd or env has null 528: * entries 529: * @throws IndexOutOfBoundsException if cmd is length 0 530: * @since 1.3 531: */ 532: public Process exec(String[] cmd, String[] env, File dir) 533: throws IOException 534: { 535: SecurityManager sm = SecurityManager.current; // Be thread-safe! 536: if (sm != null) 537: sm.checkExec(cmd[0]); 538: return execInternal(cmd, env, dir); 539: } 540: 541: /** 542: * Returns the number of available processors currently available to the 543: * virtual machine. This number may change over time; so a multi-processor 544: * program want to poll this to determine maximal resource usage. 545: * 546: * @return the number of processors available, at least 1 547: */ 548: public native int availableProcessors(); 549: 550: /** 551: * Find out how much memory is still free for allocating Objects on the heap. 552: * 553: * @return the number of bytes of free memory for more Objects 554: */ 555: public native long freeMemory(); 556: 557: /** 558: * Find out how much memory total is available on the heap for allocating 559: * Objects. 560: * 561: * @return the total number of bytes of memory for Objects 562: */ 563: public native long totalMemory(); 564: 565: /** 566: * Returns the maximum amount of memory the virtual machine can attempt to 567: * use. This may be <code>Long.MAX_VALUE</code> if there is no inherent 568: * limit (or if you really do have a 8 exabyte memory!). 569: * 570: * @return the maximum number of bytes the virtual machine will attempt 571: * to allocate 572: */ 573: public native long maxMemory(); 574: 575: /** 576: * Run the garbage collector. This method is more of a suggestion than 577: * anything. All this method guarantees is that the garbage collector will 578: * have "done its best" by the time it returns. Notice that garbage 579: * collection takes place even without calling this method. 580: */ 581: public native void gc(); 582: 583: /** 584: * Run finalization on all Objects that are waiting to be finalized. Again, 585: * a suggestion, though a stronger one than {@link #gc()}. This calls the 586: * <code>finalize</code> method of all objects waiting to be collected. 587: * 588: * @see #finalize() 589: */ 590: public native void runFinalization(); 591: 592: /** 593: * Tell the VM to trace every bytecode instruction that executes (print out 594: * a trace of it). No guarantees are made as to where it will be printed, 595: * and the VM is allowed to ignore this request. 596: * 597: * @param on whether to turn instruction tracing on 598: */ 599: public native void traceInstructions(boolean on); 600: 601: /** 602: * Tell the VM to trace every method call that executes (print out a trace 603: * of it). No guarantees are made as to where it will be printed, and the 604: * VM is allowed to ignore this request. 605: * 606: * @param on whether to turn method tracing on 607: */ 608: public native void traceMethodCalls(boolean on); 609: 610: /** 611: * Load a native library using the system-dependent filename. This is similar 612: * to loadLibrary, except the only name mangling done is inserting "_g" 613: * before the final ".so" if the VM was invoked by the name "java_g". There 614: * may be a security check, of <code>checkLink</code>. 615: * 616: * @param filename the file to load 617: * @throws SecurityException if permission is denied 618: * @throws UnsatisfiedLinkError if the library is not found 619: */ 620: public void load(String filename) 621: { 622: SecurityManager sm = SecurityManager.current; // Be thread-safe! 623: if (sm != null) 624: sm.checkLink(filename); 625: _load(filename, false); 626: } 627: 628: /** 629: * Load a native library using a system-independent "short name" for the 630: * library. It will be transformed to a correct filename in a 631: * system-dependent manner (for example, in Windows, "mylib" will be turned 632: * into "mylib.dll"). This is done as follows: if the context that called 633: * load has a ClassLoader cl, then <code>cl.findLibrary(libpath)</code> is 634: * used to convert the name. If that result was null, or there was no class 635: * loader, this searches each directory of the system property 636: * <code>java.library.path</code> for a file named 637: * <code>System.mapLibraryName(libname)</code>. There may be a security 638: * check, of <code>checkLink</code>. 639: * 640: * @param libname the library to load 641: * 642: * @throws SecurityException if permission is denied 643: * @throws UnsatisfiedLinkError if the library is not found 644: * 645: * @see System#mapLibraryName(String) 646: * @see ClassLoader#findLibrary(String) 647: */ 648: public void loadLibrary(String libname) 649: { 650: // This is different from the Classpath implementation, but I 651: // believe it is more correct. 652: SecurityManager sm = SecurityManager.current; // Be thread-safe! 653: if (sm != null) 654: sm.checkLink(libname); 655: _load(libname, true); 656: } 657: 658: /** 659: * Return a localized version of this InputStream, meaning all characters 660: * are localized before they come out the other end. 661: * 662: * @param in the stream to localize 663: * @return the localized stream 664: * @deprecated <code>InputStreamReader</code> is the preferred way to read 665: * local encodings 666: */ 667: public InputStream getLocalizedInputStream(InputStream in) 668: { 669: return in; 670: } 671: 672: /** 673: * Return a localized version of this OutputStream, meaning all characters 674: * are localized before they are sent to the other end. 675: * 676: * @param out the stream to localize 677: * @return the localized stream 678: * @deprecated <code>OutputStreamWriter</code> is the preferred way to write 679: * local encodings 680: */ 681: public OutputStream getLocalizedOutputStream(OutputStream out) 682: { 683: return out; 684: } 685: 686: /** 687: * Native method that actually shuts down the virtual machine. 688: * 689: * @param status the status to end the process with 690: */ 691: native void exitInternal(int status); 692: 693: /** 694: * Load a file. If it has already been loaded, do nothing. The name has 695: * already been mapped to a true filename. 696: * 697: * @param filename the file to load 698: * @param do_search True if we should search the load path for the file 699: */ 700: native void _load(String filename, boolean do_search); 701: 702: /** 703: *This is a helper function for the ClassLoader which can load 704: * compiled libraries. Returns true if library (which is just the 705: * base name -- path searching is done by this function) was loaded, 706: * false otherwise. 707: */ 708: native boolean loadLibraryInternal(String libname); 709: 710: /** 711: * A helper for Runtime static initializer which does some internal native 712: * initialization. 713: */ 714: private static native void init (); 715: 716: /** 717: * Run finalizers when exiting. 718: */ 719: private native void runFinalizationForExit(); 720: 721: /** 722: * Map a system-independent "short name" to the full file name, and append 723: * it to the path. 724: * XXX This method is being replaced by System.mapLibraryName. 725: * 726: * @param pathname the path 727: * @param libname the short version of the library name 728: * @return the full filename 729: */ 730: static native String nativeGetLibname(String pathname, String libname); 731: 732: /** 733: * Execute a process. The command line has already been tokenized, and 734: * the environment should contain name=value mappings. If directory is null, 735: * use the current working directory; otherwise start the process in that 736: * directory. 737: * 738: * @param cmd the non-null command tokens 739: * @param env the non-null environment setup 740: * @param dir the directory to use, may be null 741: * @return the newly created process 742: * @throws NullPointerException if cmd or env have null elements 743: * @throws IOException if the exec fails 744: */ 745: native Process execInternal(String[] cmd, String[] env, File dir) 746: throws IOException; 747: } // class Runtime