| /* Runtime.java -- access to the VM process |
| Copyright (C) 1998, 2002, 2003, 2004, 2005, 2006 Free Software Foundation |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.lang; |
| |
| import gnu.classpath.SystemProperties; |
| |
| import java.io.File; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.OutputStream; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.Set; |
| import java.util.StringTokenizer; |
| |
| /** |
| * Runtime represents the Virtual Machine. |
| * |
| * @author John Keiser |
| * @author Eric Blake (ebb9@email.byu.edu) |
| * @author Jeroen Frijters |
| */ |
| // No idea why this class isn't final, since you can't build a subclass! |
| public class Runtime |
| { |
| /** |
| * The library path, to search when loading libraries. We can also safely use |
| * this as a lock for synchronization. |
| */ |
| private final String[] libpath; |
| |
| static |
| { |
| init(); |
| } |
| |
| /** |
| * The thread that started the exit sequence. Access to this field must |
| * be thread-safe; lock on libpath to avoid deadlock with user code. |
| * <code>runFinalization()</code> may want to look at this to see if ALL |
| * finalizers should be run, because the virtual machine is about to halt. |
| */ |
| private Thread exitSequence; |
| |
| /** |
| * All shutdown hooks. This is initialized lazily, and set to null once all |
| * shutdown hooks have run. Access to this field must be thread-safe; lock |
| * on libpath to avoid deadlock with user code. |
| */ |
| private Set shutdownHooks; |
| |
| /** True if we should finalize on exit. */ |
| private boolean finalizeOnExit; |
| |
| /** |
| * The one and only runtime instance. |
| */ |
| private static final Runtime current = new Runtime(); |
| |
| /** |
| * Not instantiable by a user, this should only create one instance. |
| */ |
| private Runtime() |
| { |
| if (current != null) |
| throw new InternalError("Attempt to recreate Runtime"); |
| |
| // We don't use libpath in the libgcj implementation. We still |
| // set it to something to allow the various synchronizations to |
| // work. |
| libpath = new String[0]; |
| } |
| |
| /** |
| * Get the current Runtime object for this JVM. This is necessary to access |
| * the many instance methods of this class. |
| * |
| * @return the current Runtime object |
| */ |
| public static Runtime getRuntime() |
| { |
| return current; |
| } |
| |
| /** |
| * Exit the Java runtime. This method will either throw a SecurityException |
| * or it will never return. The status code is returned to the system; often |
| * a non-zero status code indicates an abnormal exit. Of course, there is a |
| * security check, <code>checkExit(status)</code>. |
| * |
| * <p>First, all shutdown hooks are run, in unspecified order, and |
| * concurrently. Next, if finalization on exit has been enabled, all pending |
| * finalizers are run. Finally, the system calls <code>halt</code>.</p> |
| * |
| * <p>If this is run a second time after shutdown has already started, there |
| * are two actions. If shutdown hooks are still executing, it blocks |
| * indefinitely. Otherwise, if the status is nonzero it halts immediately; |
| * if it is zero, it blocks indefinitely. This is typically called by |
| * <code>System.exit</code>.</p> |
| * |
| * @param status the status to exit with |
| * @throws SecurityException if permission is denied |
| * @see #addShutdownHook(Thread) |
| * @see #runFinalizersOnExit(boolean) |
| * @see #runFinalization() |
| * @see #halt(int) |
| */ |
| public void exit(int status) |
| { |
| SecurityManager sm = SecurityManager.current; // Be thread-safe! |
| if (sm != null) |
| sm.checkExit(status); |
| exitNoChecks(status); |
| } |
| |
| // Accessor to avoid adding a vtable slot. |
| static void exitNoChecksAccessor(int status) |
| { |
| current.exitNoChecks(status); |
| } |
| |
| // Private since we can't add a vtable slot in 4.1.x. |
| private void exitNoChecks(int status) |
| { |
| if (runShutdownHooks()) |
| exitInternal(status); |
| |
| // Someone else already called runShutdownHooks(). |
| // Make sure we are not/no longer in the shutdownHooks set. |
| // And wait till the thread that is calling runShutdownHooks() finishes. |
| synchronized (libpath) |
| { |
| if (shutdownHooks != null) |
| { |
| shutdownHooks.remove(Thread.currentThread()); |
| // Interrupt the exit sequence thread, in case it was waiting |
| // inside a join on our thread. |
| exitSequence.interrupt(); |
| // Shutdown hooks are still running, so we clear status to |
| // make sure we don't halt. |
| status = 0; |
| } |
| } |
| |
| // If exit() is called again after the shutdown hooks have run, but |
| // while finalization for exit is going on and the status is non-zero |
| // we halt immediately. |
| if (status != 0) |
| exitInternal(status); |
| |
| while (true) |
| try |
| { |
| exitSequence.join(); |
| } |
| catch (InterruptedException e) |
| { |
| // Ignore, we've suspended indefinitely to let all shutdown |
| // hooks complete, and to let any non-zero exits through, because |
| // this is a duplicate call to exit(0). |
| } |
| } |
| |
| /** |
| * On first invocation, run all the shutdown hooks and return true. |
| * Any subsequent invocations will simply return false. |
| * Note that it is package accessible so that VMRuntime can call it |
| * when VM exit is not triggered by a call to Runtime.exit(). |
| * |
| * @return was the current thread the first one to call this method? |
| */ |
| boolean runShutdownHooks() |
| { |
| boolean first = false; |
| synchronized (libpath) // Synch on libpath, not this, to avoid deadlock. |
| { |
| if (exitSequence == null) |
| { |
| first = true; |
| exitSequence = Thread.currentThread(); |
| if (shutdownHooks != null) |
| { |
| Iterator i = shutdownHooks.iterator(); |
| while (i.hasNext()) // Start all shutdown hooks. |
| try |
| { |
| ((Thread) i.next()).start(); |
| } |
| catch (IllegalThreadStateException e) |
| { |
| i.remove(); |
| } |
| } |
| } |
| } |
| if (first) |
| { |
| if (shutdownHooks != null) |
| { |
| // Check progress of all shutdown hooks. As a hook completes, |
| // remove it from the set. If a hook calls exit, it removes |
| // itself from the set, then waits indefinitely on the |
| // exitSequence thread. Once the set is empty, set it to null to |
| // signal all finalizer threads that halt may be called. |
| while (true) |
| { |
| Thread[] hooks; |
| synchronized (libpath) |
| { |
| hooks = new Thread[shutdownHooks.size()]; |
| shutdownHooks.toArray(hooks); |
| } |
| if (hooks.length == 0) |
| break; |
| for (int i = 0; i < hooks.length; i++) |
| { |
| try |
| { |
| synchronized (libpath) |
| { |
| if (!shutdownHooks.contains(hooks[i])) |
| continue; |
| } |
| hooks[i].join(); |
| synchronized (libpath) |
| { |
| shutdownHooks.remove(hooks[i]); |
| } |
| } |
| catch (InterruptedException x) |
| { |
| // continue waiting on the next thread |
| } |
| } |
| } |
| synchronized (libpath) |
| { |
| shutdownHooks = null; |
| } |
| } |
| // Run finalization on all finalizable objects (even if they are |
| // still reachable). |
| runFinalizationForExit(); |
| } |
| return first; |
| } |
| |
| /** |
| * Register a new shutdown hook. This is invoked when the program exits |
| * normally (because all non-daemon threads ended, or because |
| * <code>System.exit</code> was invoked), or when the user terminates |
| * the virtual machine (such as by typing ^C, or logging off). There is |
| * a security check to add hooks, |
| * <code>RuntimePermission("shutdownHooks")</code>. |
| * |
| * <p>The hook must be an initialized, but unstarted Thread. The threads |
| * are run concurrently, and started in an arbitrary order; and user |
| * threads or daemons may still be running. Once shutdown hooks have |
| * started, they must all complete, or else you must use <code>halt</code>, |
| * to actually finish the shutdown sequence. Attempts to modify hooks |
| * after shutdown has started result in IllegalStateExceptions.</p> |
| * |
| * <p>It is imperative that you code shutdown hooks defensively, as you |
| * do not want to deadlock, and have no idea what other hooks will be |
| * running concurrently. It is also a good idea to finish quickly, as the |
| * virtual machine really wants to shut down!</p> |
| * |
| * <p>There are no guarantees that such hooks will run, as there are ways |
| * to forcibly kill a process. But in such a drastic case, shutdown hooks |
| * would do little for you in the first place.</p> |
| * |
| * @param hook an initialized, unstarted Thread |
| * @throws IllegalArgumentException if the hook is already registered or run |
| * @throws IllegalStateException if the virtual machine is already in |
| * the shutdown sequence |
| * @throws SecurityException if permission is denied |
| * @since 1.3 |
| * @see #removeShutdownHook(Thread) |
| * @see #exit(int) |
| * @see #halt(int) |
| */ |
| public void addShutdownHook(Thread hook) |
| { |
| SecurityManager sm = SecurityManager.current; // Be thread-safe! |
| if (sm != null) |
| sm.checkPermission(new RuntimePermission("shutdownHooks")); |
| if (hook.isAlive() || hook.getThreadGroup() == null) |
| throw new IllegalArgumentException("The hook thread " + hook + " must not have been already run or started"); |
| synchronized (libpath) |
| { |
| if (exitSequence != null) |
| throw new IllegalStateException("The Virtual Machine is exiting. It is not possible anymore to add any hooks"); |
| if (shutdownHooks == null) |
| shutdownHooks = new HashSet(); // Lazy initialization. |
| if (! shutdownHooks.add(hook)) |
| throw new IllegalArgumentException(hook.toString() + " had already been inserted"); |
| } |
| } |
| |
| /** |
| * De-register a shutdown hook. As when you registered it, there is a |
| * security check to remove hooks, |
| * <code>RuntimePermission("shutdownHooks")</code>. |
| * |
| * @param hook the hook to remove |
| * @return true if the hook was successfully removed, false if it was not |
| * registered in the first place |
| * @throws IllegalStateException if the virtual machine is already in |
| * the shutdown sequence |
| * @throws SecurityException if permission is denied |
| * @since 1.3 |
| * @see #addShutdownHook(Thread) |
| * @see #exit(int) |
| * @see #halt(int) |
| */ |
| public boolean removeShutdownHook(Thread hook) |
| { |
| SecurityManager sm = SecurityManager.current; // Be thread-safe! |
| if (sm != null) |
| sm.checkPermission(new RuntimePermission("shutdownHooks")); |
| synchronized (libpath) |
| { |
| if (exitSequence != null) |
| throw new IllegalStateException(); |
| if (shutdownHooks != null) |
| return shutdownHooks.remove(hook); |
| } |
| return false; |
| } |
| |
| /** |
| * Forcibly terminate the virtual machine. This call never returns. It is |
| * much more severe than <code>exit</code>, as it bypasses all shutdown |
| * hooks and initializers. Use caution in calling this! Of course, there is |
| * a security check, <code>checkExit(status)</code>. |
| * |
| * @param status the status to exit with |
| * @throws SecurityException if permission is denied |
| * @since 1.3 |
| * @see #exit(int) |
| * @see #addShutdownHook(Thread) |
| */ |
| public void halt(int status) |
| { |
| SecurityManager sm = SecurityManager.current; // Be thread-safe! |
| if (sm != null) |
| sm.checkExit(status); |
| exitInternal(status); |
| } |
| |
| /** |
| * Tell the VM to run the finalize() method on every single Object before |
| * it exits. Note that the JVM may still exit abnormally and not perform |
| * this, so you still don't have a guarantee. And besides that, this is |
| * inherently unsafe in multi-threaded code, as it may result in deadlock |
| * as multiple threads compete to manipulate objects. This value defaults to |
| * <code>false</code>. There is a security check, <code>checkExit(0)</code>. |
| * |
| * @param finalizeOnExit whether to finalize all Objects on exit |
| * @throws SecurityException if permission is denied |
| * @see #exit(int) |
| * @see #gc() |
| * @since 1.1 |
| * @deprecated never rely on finalizers to do a clean, thread-safe, |
| * mop-up from your code |
| */ |
| public static void runFinalizersOnExit(boolean finalizeOnExit) |
| { |
| SecurityManager sm = SecurityManager.current; // Be thread-safe! |
| if (sm != null) |
| sm.checkExit(0); |
| current.finalizeOnExit = finalizeOnExit; |
| } |
| |
| /** |
| * Create a new subprocess with the specified command line. Calls |
| * <code>exec(cmdline, null, null)</code>. A security check is performed, |
| * <code>checkExec</code>. |
| * |
| * @param cmdline the command to call |
| * @return the Process object |
| * @throws SecurityException if permission is denied |
| * @throws IOException if an I/O error occurs |
| * @throws NullPointerException if cmdline is null |
| * @throws IndexOutOfBoundsException if cmdline is "" |
| */ |
| public Process exec(String cmdline) throws IOException |
| { |
| return exec(cmdline, null, null); |
| } |
| |
| /** |
| * Create a new subprocess with the specified command line and environment. |
| * If the environment is null, the process inherits the environment of |
| * this process. Calls <code>exec(cmdline, env, null)</code>. A security |
| * check is performed, <code>checkExec</code>. |
| * |
| * @param cmdline the command to call |
| * @param env the environment to use, in the format name=value |
| * @return the Process object |
| * @throws SecurityException if permission is denied |
| * @throws IOException if an I/O error occurs |
| * @throws NullPointerException if cmdline is null, or env has null entries |
| * @throws IndexOutOfBoundsException if cmdline is "" |
| */ |
| public Process exec(String cmdline, String[] env) throws IOException |
| { |
| return exec(cmdline, env, null); |
| } |
| |
| /** |
| * Create a new subprocess with the specified command line, environment, and |
| * working directory. If the environment is null, the process inherits the |
| * environment of this process. If the directory is null, the process uses |
| * the current working directory. This splits cmdline into an array, using |
| * the default StringTokenizer, then calls |
| * <code>exec(cmdArray, env, dir)</code>. A security check is performed, |
| * <code>checkExec</code>. |
| * |
| * @param cmdline the command to call |
| * @param env the environment to use, in the format name=value |
| * @param dir the working directory to use |
| * @return the Process object |
| * @throws SecurityException if permission is denied |
| * @throws IOException if an I/O error occurs |
| * @throws NullPointerException if cmdline is null, or env has null entries |
| * @throws IndexOutOfBoundsException if cmdline is "" |
| * @since 1.3 |
| */ |
| public Process exec(String cmdline, String[] env, File dir) |
| throws IOException |
| { |
| StringTokenizer t = new StringTokenizer(cmdline); |
| String[] cmd = new String[t.countTokens()]; |
| for (int i = 0; i < cmd.length; i++) |
| cmd[i] = t.nextToken(); |
| return exec(cmd, env, dir); |
| } |
| |
| /** |
| * Create a new subprocess with the specified command line, already |
| * tokenized. Calls <code>exec(cmd, null, null)</code>. A security check |
| * is performed, <code>checkExec</code>. |
| * |
| * @param cmd the command to call |
| * @return the Process object |
| * @throws SecurityException if permission is denied |
| * @throws IOException if an I/O error occurs |
| * @throws NullPointerException if cmd is null, or has null entries |
| * @throws IndexOutOfBoundsException if cmd is length 0 |
| */ |
| public Process exec(String[] cmd) throws IOException |
| { |
| return exec(cmd, null, null); |
| } |
| |
| /** |
| * Create a new subprocess with the specified command line, already |
| * tokenized, and specified environment. If the environment is null, the |
| * process inherits the environment of this process. Calls |
| * <code>exec(cmd, env, null)</code>. A security check is performed, |
| * <code>checkExec</code>. |
| * |
| * @param cmd the command to call |
| * @param env the environment to use, in the format name=value |
| * @return the Process object |
| * @throws SecurityException if permission is denied |
| * @throws IOException if an I/O error occurs |
| * @throws NullPointerException if cmd is null, or cmd or env has null |
| * entries |
| * @throws IndexOutOfBoundsException if cmd is length 0 |
| */ |
| public Process exec(String[] cmd, String[] env) throws IOException |
| { |
| return exec(cmd, env, null); |
| } |
| |
| /** |
| * Create a new subprocess with the specified command line, already |
| * tokenized, and the specified environment and working directory. If the |
| * environment is null, the process inherits the environment of this |
| * process. If the directory is null, the process uses the current working |
| * directory. A security check is performed, <code>checkExec</code>. |
| * |
| * @param cmd the command to call |
| * @param env the environment to use, in the format name=value |
| * @param dir the working directory to use |
| * @return the Process object |
| * @throws SecurityException if permission is denied |
| * @throws IOException if an I/O error occurs |
| * @throws NullPointerException if cmd is null, or cmd or env has null |
| * entries |
| * @throws IndexOutOfBoundsException if cmd is length 0 |
| * @since 1.3 |
| */ |
| public Process exec(String[] cmd, String[] env, File dir) |
| throws IOException |
| { |
| SecurityManager sm = SecurityManager.current; // Be thread-safe! |
| if (sm != null) |
| sm.checkExec(cmd[0]); |
| return execInternal(cmd, env, dir); |
| } |
| |
| /** |
| * Returns the number of available processors currently available to the |
| * virtual machine. This number may change over time; so a multi-processor |
| * program want to poll this to determine maximal resource usage. |
| * |
| * @return the number of processors available, at least 1 |
| */ |
| public native int availableProcessors(); |
| |
| /** |
| * Find out how much memory is still free for allocating Objects on the heap. |
| * |
| * @return the number of bytes of free memory for more Objects |
| */ |
| public native long freeMemory(); |
| |
| /** |
| * Find out how much memory total is available on the heap for allocating |
| * Objects. |
| * |
| * @return the total number of bytes of memory for Objects |
| */ |
| public native long totalMemory(); |
| |
| /** |
| * Returns the maximum amount of memory the virtual machine can attempt to |
| * use. This may be <code>Long.MAX_VALUE</code> if there is no inherent |
| * limit (or if you really do have a 8 exabyte memory!). |
| * |
| * @return the maximum number of bytes the virtual machine will attempt |
| * to allocate |
| */ |
| public native long maxMemory(); |
| |
| /** |
| * Run the garbage collector. This method is more of a suggestion than |
| * anything. All this method guarantees is that the garbage collector will |
| * have "done its best" by the time it returns. Notice that garbage |
| * collection takes place even without calling this method. |
| */ |
| public native void gc(); |
| |
| /** |
| * Run finalization on all Objects that are waiting to be finalized. Again, |
| * a suggestion, though a stronger one than {@link #gc()}. This calls the |
| * <code>finalize</code> method of all objects waiting to be collected. |
| * |
| * @see #finalize() |
| */ |
| public native void runFinalization(); |
| |
| /** |
| * Tell the VM to trace every bytecode instruction that executes (print out |
| * a trace of it). No guarantees are made as to where it will be printed, |
| * and the VM is allowed to ignore this request. |
| * |
| * @param on whether to turn instruction tracing on |
| */ |
| public native void traceInstructions(boolean on); |
| |
| /** |
| * Tell the VM to trace every method call that executes (print out a trace |
| * of it). No guarantees are made as to where it will be printed, and the |
| * VM is allowed to ignore this request. |
| * |
| * @param on whether to turn method tracing on |
| */ |
| public native void traceMethodCalls(boolean on); |
| |
| /** |
| * Load a native library using the system-dependent filename. This is similar |
| * to loadLibrary, except the only name mangling done is inserting "_g" |
| * before the final ".so" if the VM was invoked by the name "java_g". There |
| * may be a security check, of <code>checkLink</code>. |
| * |
| * @param filename the file to load |
| * @throws SecurityException if permission is denied |
| * @throws UnsatisfiedLinkError if the library is not found |
| */ |
| public void load(String filename) |
| { |
| SecurityManager sm = SecurityManager.current; // Be thread-safe! |
| if (sm != null) |
| sm.checkLink(filename); |
| _load(filename, false); |
| } |
| |
| /** |
| * Load a native library using a system-independent "short name" for the |
| * library. It will be transformed to a correct filename in a |
| * system-dependent manner (for example, in Windows, "mylib" will be turned |
| * into "mylib.dll"). This is done as follows: if the context that called |
| * load has a ClassLoader cl, then <code>cl.findLibrary(libpath)</code> is |
| * used to convert the name. If that result was null, or there was no class |
| * loader, this searches each directory of the system property |
| * <code>java.library.path</code> for a file named |
| * <code>System.mapLibraryName(libname)</code>. There may be a security |
| * check, of <code>checkLink</code>. |
| * |
| * @param libname the library to load |
| * |
| * @throws SecurityException if permission is denied |
| * @throws UnsatisfiedLinkError if the library is not found |
| * |
| * @see System#mapLibraryName(String) |
| * @see ClassLoader#findLibrary(String) |
| */ |
| public void loadLibrary(String libname) |
| { |
| // This is different from the Classpath implementation, but I |
| // believe it is more correct. |
| SecurityManager sm = SecurityManager.current; // Be thread-safe! |
| if (sm != null) |
| sm.checkLink(libname); |
| _load(libname, true); |
| } |
| |
| /** |
| * Return a localized version of this InputStream, meaning all characters |
| * are localized before they come out the other end. |
| * |
| * @param in the stream to localize |
| * @return the localized stream |
| * @deprecated <code>InputStreamReader</code> is the preferred way to read |
| * local encodings |
| */ |
| public InputStream getLocalizedInputStream(InputStream in) |
| { |
| return in; |
| } |
| |
| /** |
| * Return a localized version of this OutputStream, meaning all characters |
| * are localized before they are sent to the other end. |
| * |
| * @param out the stream to localize |
| * @return the localized stream |
| * @deprecated <code>OutputStreamWriter</code> is the preferred way to write |
| * local encodings |
| */ |
| public OutputStream getLocalizedOutputStream(OutputStream out) |
| { |
| return out; |
| } |
| |
| /** |
| * Native method that actually shuts down the virtual machine. |
| * |
| * @param status the status to end the process with |
| */ |
| native void exitInternal(int status); |
| |
| /** |
| * Load a file. If it has already been loaded, do nothing. The name has |
| * already been mapped to a true filename. |
| * |
| * @param filename the file to load |
| * @param do_search True if we should search the load path for the file |
| */ |
| native void _load(String filename, boolean do_search); |
| |
| /** |
| *This is a helper function for the ClassLoader which can load |
| * compiled libraries. Returns true if library (which is just the |
| * base name -- path searching is done by this function) was loaded, |
| * false otherwise. |
| */ |
| native boolean loadLibraryInternal(String libname); |
| |
| /** |
| * A helper for Runtime static initializer which does some internal native |
| * initialization. |
| */ |
| private static native void init (); |
| |
| /** |
| * Run finalizers when exiting. |
| */ |
| private native void runFinalizationForExit(); |
| |
| /** |
| * Map a system-independent "short name" to the full file name, and append |
| * it to the path. |
| * XXX This method is being replaced by System.mapLibraryName. |
| * |
| * @param pathname the path |
| * @param libname the short version of the library name |
| * @return the full filename |
| */ |
| static native String nativeGetLibname(String pathname, String libname); |
| |
| /** |
| * Execute a process. The command line has already been tokenized, and |
| * the environment should contain name=value mappings. If directory is null, |
| * use the current working directory; otherwise start the process in that |
| * directory. |
| * |
| * @param cmd the non-null command tokens |
| * @param env the non-null environment setup |
| * @param dir the directory to use, may be null |
| * @return the newly created process |
| * @throws NullPointerException if cmd or env have null elements |
| * @throws IOException if the exec fails |
| */ |
| native Process execInternal(String[] cmd, String[] env, File dir) |
| throws IOException; |
| } // class Runtime |
