| /* |
| * Copyright (c) 1995, 2006, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.lang; |
| |
| import java.io.*; |
| import java.util.StringTokenizer; |
| |
| /** |
| * Every Java application has a single instance of class |
| * <code>Runtime</code> that allows the application to interface with |
| * the environment in which the application is running. The current |
| * runtime can be obtained from the <code>getRuntime</code> method. |
| * <p> |
| * An application cannot create its own instance of this class. |
| * |
| * @author unascribed |
| * @see java.lang.Runtime#getRuntime() |
| * @since JDK1.0 |
| */ |
| |
| public class Runtime { |
| private static Runtime currentRuntime = new Runtime(); |
| |
| /** |
| * Returns the runtime object associated with the current Java application. |
| * Most of the methods of class <code>Runtime</code> are instance |
| * methods and must be invoked with respect to the current runtime object. |
| * |
| * @return the <code>Runtime</code> object associated with the current |
| * Java application. |
| */ |
| public static Runtime getRuntime() { |
| return currentRuntime; |
| } |
| |
| /** Don't let anyone else instantiate this class */ |
| private Runtime() {} |
| |
| /** |
| * Terminates the currently running Java virtual machine by initiating its |
| * shutdown sequence. This method never returns normally. The argument |
| * serves as a status code; by convention, a nonzero status code indicates |
| * abnormal termination. |
| * |
| * <p> The virtual machine's shutdown sequence consists of two phases. In |
| * the first phase all registered {@link #addShutdownHook shutdown hooks}, |
| * if any, are started in some unspecified order and allowed to run |
| * concurrently until they finish. In the second phase all uninvoked |
| * finalizers are run if {@link #runFinalizersOnExit finalization-on-exit} |
| * has been enabled. Once this is done the virtual machine {@link #halt |
| * halts}. |
| * |
| * <p> If this method is invoked after the virtual machine has begun its |
| * shutdown sequence then if shutdown hooks are being run this method will |
| * block indefinitely. If shutdown hooks have already been run and on-exit |
| * finalization has been enabled then this method halts the virtual machine |
| * with the given status code if the status is nonzero; otherwise, it |
| * blocks indefinitely. |
| * |
| * <p> The <tt>{@link System#exit(int) System.exit}</tt> method is the |
| * conventional and convenient means of invoking this method. <p> |
| * |
| * @param status |
| * Termination status. By convention, a nonzero status code |
| * indicates abnormal termination. |
| * |
| * @throws SecurityException |
| * If a security manager is present and its <tt>{@link |
| * SecurityManager#checkExit checkExit}</tt> method does not permit |
| * exiting with the specified status |
| * |
| * @see java.lang.SecurityException |
| * @see java.lang.SecurityManager#checkExit(int) |
| * @see #addShutdownHook |
| * @see #removeShutdownHook |
| * @see #runFinalizersOnExit |
| * @see #halt(int) |
| */ |
| public void exit(int status) { |
| SecurityManager security = System.getSecurityManager(); |
| if (security != null) { |
| security.checkExit(status); |
| } |
| Shutdown.exit(status); |
| } |
| |
| /** |
| * Registers a new virtual-machine shutdown hook. |
| * |
| * <p> The Java virtual machine <i>shuts down</i> in response to two kinds |
| * of events: |
| * |
| * <ul> |
| * |
| * <p> <li> The program <i>exits</i> normally, when the last non-daemon |
| * thread exits or when the <tt>{@link #exit exit}</tt> (equivalently, |
| * <tt>{@link System#exit(int) System.exit}</tt>) method is invoked, or |
| * |
| * <p> <li> The virtual machine is <i>terminated</i> in response to a |
| * user interrupt, such as typing <tt>^C</tt>, or a system-wide event, |
| * such as user logoff or system shutdown. |
| * |
| * </ul> |
| * |
| * <p> A <i>shutdown hook</i> is simply an initialized but unstarted |
| * thread. When the virtual machine begins its shutdown sequence it will |
| * start all registered shutdown hooks in some unspecified order and let |
| * them run concurrently. When all the hooks have finished it will then |
| * run all uninvoked finalizers if finalization-on-exit has been enabled. |
| * Finally, the virtual machine will halt. Note that daemon threads will |
| * continue to run during the shutdown sequence, as will non-daemon threads |
| * if shutdown was initiated by invoking the <tt>{@link #exit exit}</tt> |
| * method. |
| * |
| * <p> Once the shutdown sequence has begun it can be stopped only by |
| * invoking the <tt>{@link #halt halt}</tt> method, which forcibly |
| * terminates the virtual machine. |
| * |
| * <p> Once the shutdown sequence has begun it is impossible to register a |
| * new shutdown hook or de-register a previously-registered hook. |
| * Attempting either of these operations will cause an |
| * <tt>{@link IllegalStateException}</tt> to be thrown. |
| * |
| * <p> Shutdown hooks run at a delicate time in the life cycle of a virtual |
| * machine and should therefore be coded defensively. They should, in |
| * particular, be written to be thread-safe and to avoid deadlocks insofar |
| * as possible. They should also not rely blindly upon services that may |
| * have registered their own shutdown hooks and therefore may themselves in |
| * the process of shutting down. Attempts to use other thread-based |
| * services such as the AWT event-dispatch thread, for example, may lead to |
| * deadlocks. |
| * |
| * <p> Shutdown hooks should also finish their work quickly. When a |
| * program invokes <tt>{@link #exit exit}</tt> the expectation is |
| * that the virtual machine will promptly shut down and exit. When the |
| * virtual machine is terminated due to user logoff or system shutdown the |
| * underlying operating system may only allow a fixed amount of time in |
| * which to shut down and exit. It is therefore inadvisable to attempt any |
| * user interaction or to perform a long-running computation in a shutdown |
| * hook. |
| * |
| * <p> Uncaught exceptions are handled in shutdown hooks just as in any |
| * other thread, by invoking the <tt>{@link ThreadGroup#uncaughtException |
| * uncaughtException}</tt> method of the thread's <tt>{@link |
| * ThreadGroup}</tt> object. The default implementation of this method |
| * prints the exception's stack trace to <tt>{@link System#err}</tt> and |
| * terminates the thread; it does not cause the virtual machine to exit or |
| * halt. |
| * |
| * <p> In rare circumstances the virtual machine may <i>abort</i>, that is, |
| * stop running without shutting down cleanly. This occurs when the |
| * virtual machine is terminated externally, for example with the |
| * <tt>SIGKILL</tt> signal on Unix or the <tt>TerminateProcess</tt> call on |
| * Microsoft Windows. The virtual machine may also abort if a native |
| * method goes awry by, for example, corrupting internal data structures or |
| * attempting to access nonexistent memory. If the virtual machine aborts |
| * then no guarantee can be made about whether or not any shutdown hooks |
| * will be run. <p> |
| * |
| * @param hook |
| * An initialized but unstarted <tt>{@link Thread}</tt> object |
| * |
| * @throws IllegalArgumentException |
| * If the specified hook has already been registered, |
| * or if it can be determined that the hook is already running or |
| * has already been run |
| * |
| * @throws IllegalStateException |
| * If the virtual machine is already in the process |
| * of shutting down |
| * |
| * @throws SecurityException |
| * If a security manager is present and it denies |
| * <tt>{@link RuntimePermission}("shutdownHooks")</tt> |
| * |
| * @see #removeShutdownHook |
| * @see #halt(int) |
| * @see #exit(int) |
| * @since 1.3 |
| */ |
| public void addShutdownHook(Thread hook) { |
| SecurityManager sm = System.getSecurityManager(); |
| if (sm != null) { |
| sm.checkPermission(new RuntimePermission("shutdownHooks")); |
| } |
| ApplicationShutdownHooks.add(hook); |
| } |
| |
| /** |
| * De-registers a previously-registered virtual-machine shutdown hook. <p> |
| * |
| * @param hook the hook to remove |
| * @return <tt>true</tt> if the specified hook had previously been |
| * registered and was successfully de-registered, <tt>false</tt> |
| * otherwise. |
| * |
| * @throws IllegalStateException |
| * If the virtual machine is already in the process of shutting |
| * down |
| * |
| * @throws SecurityException |
| * If a security manager is present and it denies |
| * <tt>{@link RuntimePermission}("shutdownHooks")</tt> |
| * |
| * @see #addShutdownHook |
| * @see #exit(int) |
| * @since 1.3 |
| */ |
| public boolean removeShutdownHook(Thread hook) { |
| SecurityManager sm = System.getSecurityManager(); |
| if (sm != null) { |
| sm.checkPermission(new RuntimePermission("shutdownHooks")); |
| } |
| return ApplicationShutdownHooks.remove(hook); |
| } |
| |
| /** |
| * Forcibly terminates the currently running Java virtual machine. This |
| * method never returns normally. |
| * |
| * <p> This method should be used with extreme caution. Unlike the |
| * <tt>{@link #exit exit}</tt> method, this method does not cause shutdown |
| * hooks to be started and does not run uninvoked finalizers if |
| * finalization-on-exit has been enabled. If the shutdown sequence has |
| * already been initiated then this method does not wait for any running |
| * shutdown hooks or finalizers to finish their work. <p> |
| * |
| * @param status |
| * Termination status. By convention, a nonzero status code |
| * indicates abnormal termination. If the <tt>{@link Runtime#exit |
| * exit}</tt> (equivalently, <tt>{@link System#exit(int) |
| * System.exit}</tt>) method has already been invoked then this |
| * status code will override the status code passed to that method. |
| * |
| * @throws SecurityException |
| * If a security manager is present and its <tt>{@link |
| * SecurityManager#checkExit checkExit}</tt> method does not permit |
| * an exit with the specified status |
| * |
| * @see #exit |
| * @see #addShutdownHook |
| * @see #removeShutdownHook |
| * @since 1.3 |
| */ |
| public void halt(int status) { |
| SecurityManager sm = System.getSecurityManager(); |
| if (sm != null) { |
| sm.checkExit(status); |
| } |
| Shutdown.halt(status); |
| } |
| |
| /** |
| * Enable or disable finalization on exit; doing so specifies that the |
| * finalizers of all objects that have finalizers that have not yet been |
| * automatically invoked are to be run before the Java runtime exits. |
| * By default, finalization on exit is disabled. |
| * |
| * <p>If there is a security manager, |
| * its <code>checkExit</code> method is first called |
| * with 0 as its argument to ensure the exit is allowed. |
| * This could result in a SecurityException. |
| * |
| * @param value true to enable finalization on exit, false to disable |
| * @deprecated This method is inherently unsafe. It may result in |
| * finalizers being called on live objects while other threads are |
| * concurrently manipulating those objects, resulting in erratic |
| * behavior or deadlock. |
| * |
| * @throws SecurityException |
| * if a security manager exists and its <code>checkExit</code> |
| * method doesn't allow the exit. |
| * |
| * @see java.lang.Runtime#exit(int) |
| * @see java.lang.Runtime#gc() |
| * @see java.lang.SecurityManager#checkExit(int) |
| * @since JDK1.1 |
| */ |
| @Deprecated |
| public static void runFinalizersOnExit(boolean value) { |
| SecurityManager security = System.getSecurityManager(); |
| if (security != null) { |
| try { |
| security.checkExit(0); |
| } catch (SecurityException e) { |
| throw new SecurityException("runFinalizersOnExit"); |
| } |
| } |
| Shutdown.setRunFinalizersOnExit(value); |
| } |
| |
| /** |
| * Executes the specified string command in a separate process. |
| * |
| * <p>This is a convenience method. An invocation of the form |
| * <tt>exec(command)</tt> |
| * behaves in exactly the same way as the invocation |
| * <tt>{@link #exec(String, String[], File) exec}(command, null, null)</tt>. |
| * |
| * @param command a specified system command. |
| * |
| * @return A new {@link Process} object for managing the subprocess |
| * |
| * @throws SecurityException |
| * If a security manager exists and its |
| * {@link SecurityManager#checkExec checkExec} |
| * method doesn't allow creation of the subprocess |
| * |
| * @throws IOException |
| * If an I/O error occurs |
| * |
| * @throws NullPointerException |
| * If <code>command</code> is <code>null</code> |
| * |
| * @throws IllegalArgumentException |
| * If <code>command</code> is empty |
| * |
| * @see #exec(String[], String[], File) |
| * @see ProcessBuilder |
| */ |
| public Process exec(String command) throws IOException { |
| return exec(command, null, null); |
| } |
| |
| /** |
| * Executes the specified string command in a separate process with the |
| * specified environment. |
| * |
| * <p>This is a convenience method. An invocation of the form |
| * <tt>exec(command, envp)</tt> |
| * behaves in exactly the same way as the invocation |
| * <tt>{@link #exec(String, String[], File) exec}(command, envp, null)</tt>. |
| * |
| * @param command a specified system command. |
| * |
| * @param envp array of strings, each element of which |
| * has environment variable settings in the format |
| * <i>name</i>=<i>value</i>, or |
| * <tt>null</tt> if the subprocess should inherit |
| * the environment of the current process. |
| * |
| * @return A new {@link Process} object for managing the subprocess |
| * |
| * @throws SecurityException |
| * If a security manager exists and its |
| * {@link SecurityManager#checkExec checkExec} |
| * method doesn't allow creation of the subprocess |
| * |
| * @throws IOException |
| * If an I/O error occurs |
| * |
| * @throws NullPointerException |
| * If <code>command</code> is <code>null</code>, |
| * or one of the elements of <code>envp</code> is <code>null</code> |
| * |
| * @throws IllegalArgumentException |
| * If <code>command</code> is empty |
| * |
| * @see #exec(String[], String[], File) |
| * @see ProcessBuilder |
| */ |
| public Process exec(String command, String[] envp) throws IOException { |
| return exec(command, envp, null); |
| } |
| |
| /** |
| * Executes the specified string command in a separate process with the |
| * specified environment and working directory. |
| * |
| * <p>This is a convenience method. An invocation of the form |
| * <tt>exec(command, envp, dir)</tt> |
| * behaves in exactly the same way as the invocation |
| * <tt>{@link #exec(String[], String[], File) exec}(cmdarray, envp, dir)</tt>, |
| * where <code>cmdarray</code> is an array of all the tokens in |
| * <code>command</code>. |
| * |
| * <p>More precisely, the <code>command</code> string is broken |
| * into tokens using a {@link StringTokenizer} created by the call |
| * <code>new {@link StringTokenizer}(command)</code> with no |
| * further modification of the character categories. The tokens |
| * produced by the tokenizer are then placed in the new string |
| * array <code>cmdarray</code>, in the same order. |
| * |
| * @param command a specified system command. |
| * |
| * @param envp array of strings, each element of which |
| * has environment variable settings in the format |
| * <i>name</i>=<i>value</i>, or |
| * <tt>null</tt> if the subprocess should inherit |
| * the environment of the current process. |
| * |
| * @param dir the working directory of the subprocess, or |
| * <tt>null</tt> if the subprocess should inherit |
| * the working directory of the current process. |
| * |
| * @return A new {@link Process} object for managing the subprocess |
| * |
| * @throws SecurityException |
| * If a security manager exists and its |
| * {@link SecurityManager#checkExec checkExec} |
| * method doesn't allow creation of the subprocess |
| * |
| * @throws IOException |
| * If an I/O error occurs |
| * |
| * @throws NullPointerException |
| * If <code>command</code> is <code>null</code>, |
| * or one of the elements of <code>envp</code> is <code>null</code> |
| * |
| * @throws IllegalArgumentException |
| * If <code>command</code> is empty |
| * |
| * @see ProcessBuilder |
| * @since 1.3 |
| */ |
| public Process exec(String command, String[] envp, File dir) |
| throws IOException { |
| if (command.length() == 0) |
| throw new IllegalArgumentException("Empty command"); |
| |
| StringTokenizer st = new StringTokenizer(command); |
| String[] cmdarray = new String[st.countTokens()]; |
| for (int i = 0; st.hasMoreTokens(); i++) |
| cmdarray[i] = st.nextToken(); |
| return exec(cmdarray, envp, dir); |
| } |
| |
| /** |
| * Executes the specified command and arguments in a separate process. |
| * |
| * <p>This is a convenience method. An invocation of the form |
| * <tt>exec(cmdarray)</tt> |
| * behaves in exactly the same way as the invocation |
| * <tt>{@link #exec(String[], String[], File) exec}(cmdarray, null, null)</tt>. |
| * |
| * @param cmdarray array containing the command to call and |
| * its arguments. |
| * |
| * @return A new {@link Process} object for managing the subprocess |
| * |
| * @throws SecurityException |
| * If a security manager exists and its |
| * {@link SecurityManager#checkExec checkExec} |
| * method doesn't allow creation of the subprocess |
| * |
| * @throws IOException |
| * If an I/O error occurs |
| * |
| * @throws NullPointerException |
| * If <code>cmdarray</code> is <code>null</code>, |
| * or one of the elements of <code>cmdarray</code> is <code>null</code> |
| * |
| * @throws IndexOutOfBoundsException |
| * If <code>cmdarray</code> is an empty array |
| * (has length <code>0</code>) |
| * |
| * @see ProcessBuilder |
| */ |
| public Process exec(String cmdarray[]) throws IOException { |
| return exec(cmdarray, null, null); |
| } |
| |
| /** |
| * Executes the specified command and arguments in a separate process |
| * with the specified environment. |
| * |
| * <p>This is a convenience method. An invocation of the form |
| * <tt>exec(cmdarray, envp)</tt> |
| * behaves in exactly the same way as the invocation |
| * <tt>{@link #exec(String[], String[], File) exec}(cmdarray, envp, null)</tt>. |
| * |
| * @param cmdarray array containing the command to call and |
| * its arguments. |
| * |
| * @param envp array of strings, each element of which |
| * has environment variable settings in the format |
| * <i>name</i>=<i>value</i>, or |
| * <tt>null</tt> if the subprocess should inherit |
| * the environment of the current process. |
| * |
| * @return A new {@link Process} object for managing the subprocess |
| * |
| * @throws SecurityException |
| * If a security manager exists and its |
| * {@link SecurityManager#checkExec checkExec} |
| * method doesn't allow creation of the subprocess |
| * |
| * @throws IOException |
| * If an I/O error occurs |
| * |
| * @throws NullPointerException |
| * If <code>cmdarray</code> is <code>null</code>, |
| * or one of the elements of <code>cmdarray</code> is <code>null</code>, |
| * or one of the elements of <code>envp</code> is <code>null</code> |
| * |
| * @throws IndexOutOfBoundsException |
| * If <code>cmdarray</code> is an empty array |
| * (has length <code>0</code>) |
| * |
| * @see ProcessBuilder |
| */ |
| public Process exec(String[] cmdarray, String[] envp) throws IOException { |
| return exec(cmdarray, envp, null); |
| } |
| |
| |
| /** |
| * Executes the specified command and arguments in a separate process with |
| * the specified environment and working directory. |
| * |
| * <p>Given an array of strings <code>cmdarray</code>, representing the |
| * tokens of a command line, and an array of strings <code>envp</code>, |
| * representing "environment" variable settings, this method creates |
| * a new process in which to execute the specified command. |
| * |
| * <p>This method checks that <code>cmdarray</code> is a valid operating |
| * system command. Which commands are valid is system-dependent, |
| * but at the very least the command must be a non-empty list of |
| * non-null strings. |
| * |
| * <p>If <tt>envp</tt> is <tt>null</tt>, the subprocess inherits the |
| * environment settings of the current process. |
| * |
| * <p>{@link ProcessBuilder#start()} is now the preferred way to |
| * start a process with a modified environment. |
| * |
| * <p>The working directory of the new subprocess is specified by <tt>dir</tt>. |
| * If <tt>dir</tt> is <tt>null</tt>, the subprocess inherits the |
| * current working directory of the current process. |
| * |
| * <p>If a security manager exists, its |
| * {@link SecurityManager#checkExec checkExec} |
| * method is invoked with the first component of the array |
| * <code>cmdarray</code> as its argument. This may result in a |
| * {@link SecurityException} being thrown. |
| * |
| * <p>Starting an operating system process is highly system-dependent. |
| * Among the many things that can go wrong are: |
| * <ul> |
| * <li>The operating system program file was not found. |
| * <li>Access to the program file was denied. |
| * <li>The working directory does not exist. |
| * </ul> |
| * |
| * <p>In such cases an exception will be thrown. The exact nature |
| * of the exception is system-dependent, but it will always be a |
| * subclass of {@link IOException}. |
| * |
| * |
| * @param cmdarray array containing the command to call and |
| * its arguments. |
| * |
| * @param envp array of strings, each element of which |
| * has environment variable settings in the format |
| * <i>name</i>=<i>value</i>, or |
| * <tt>null</tt> if the subprocess should inherit |
| * the environment of the current process. |
| * |
| * @param dir the working directory of the subprocess, or |
| * <tt>null</tt> if the subprocess should inherit |
| * the working directory of the current process. |
| * |
| * @return A new {@link Process} object for managing the subprocess |
| * |
| * @throws SecurityException |
| * If a security manager exists and its |
| * {@link SecurityManager#checkExec checkExec} |
| * method doesn't allow creation of the subprocess |
| * |
| * @throws IOException |
| * If an I/O error occurs |
| * |
| * @throws NullPointerException |
| * If <code>cmdarray</code> is <code>null</code>, |
| * or one of the elements of <code>cmdarray</code> is <code>null</code>, |
| * or one of the elements of <code>envp</code> is <code>null</code> |
| * |
| * @throws IndexOutOfBoundsException |
| * If <code>cmdarray</code> is an empty array |
| * (has length <code>0</code>) |
| * |
| * @see ProcessBuilder |
| * @since 1.3 |
| */ |
| public Process exec(String[] cmdarray, String[] envp, File dir) |
| throws IOException { |
| return new ProcessBuilder(cmdarray) |
| .environment(envp) |
| .directory(dir) |
| .start(); |
| } |
| |
| /** |
| * Returns the number of processors available to the Java virtual machine. |
| * |
| * <p> This value may change during a particular invocation of the virtual |
| * machine. Applications that are sensitive to the number of available |
| * processors should therefore occasionally poll this property and adjust |
| * their resource usage appropriately. </p> |
| * |
| * @return the maximum number of processors available to the virtual |
| * machine; never smaller than one |
| * @since 1.4 |
| */ |
| public native int availableProcessors(); |
| |
| /** |
| * Returns the amount of free memory in the Java Virtual Machine. |
| * Calling the |
| * <code>gc</code> method may result in increasing the value returned |
| * by <code>freeMemory.</code> |
| * |
| * @return an approximation to the total amount of memory currently |
| * available for future allocated objects, measured in bytes. |
| */ |
| public native long freeMemory(); |
| |
| /** |
| * Returns the total amount of memory in the Java virtual machine. |
| * The value returned by this method may vary over time, depending on |
| * the host environment. |
| * <p> |
| * Note that the amount of memory required to hold an object of any |
| * given type may be implementation-dependent. |
| * |
| * @return the total amount of memory currently available for current |
| * and future objects, measured in bytes. |
| */ |
| public native long totalMemory(); |
| |
| /** |
| * Returns the maximum amount of memory that the Java virtual machine will |
| * attempt to use. If there is no inherent limit then the value {@link |
| * java.lang.Long#MAX_VALUE} will be returned. </p> |
| * |
| * @return the maximum amount of memory that the virtual machine will |
| * attempt to use, measured in bytes |
| * @since 1.4 |
| */ |
| public native long maxMemory(); |
| |
| /** |
| * Runs the garbage collector. |
| * Calling this method suggests that the Java virtual machine expend |
| * effort toward recycling unused objects in order to make the memory |
| * they currently occupy available for quick reuse. When control |
| * returns from the method call, the virtual machine has made |
| * its best effort to recycle all discarded objects. |
| * <p> |
| * The name <code>gc</code> stands for "garbage |
| * collector". The virtual machine performs this recycling |
| * process automatically as needed, in a separate thread, even if the |
| * <code>gc</code> method is not invoked explicitly. |
| * <p> |
| * The method {@link System#gc()} is the conventional and convenient |
| * means of invoking this method. |
| */ |
| public native void gc(); |
| |
| /* Wormhole for calling java.lang.ref.Finalizer.runFinalization */ |
| private static native void runFinalization0(); |
| |
| /** |
| * Runs the finalization methods of any objects pending finalization. |
| * Calling this method suggests that the Java virtual machine expend |
| * effort toward running the <code>finalize</code> methods of objects |
| * that have been found to be discarded but whose <code>finalize</code> |
| * methods have not yet been run. When control returns from the |
| * method call, the virtual machine has made a best effort to |
| * complete all outstanding finalizations. |
| * <p> |
| * The virtual machine performs the finalization process |
| * automatically as needed, in a separate thread, if the |
| * <code>runFinalization</code> method is not invoked explicitly. |
| * <p> |
| * The method {@link System#runFinalization()} is the conventional |
| * and convenient means of invoking this method. |
| * |
| * @see java.lang.Object#finalize() |
| */ |
| public void runFinalization() { |
| runFinalization0(); |
| } |
| |
| /** |
| * Enables/Disables tracing of instructions. |
| * If the <code>boolean</code> argument is <code>true</code>, this |
| * method suggests that the Java virtual machine emit debugging |
| * information for each instruction in the virtual machine as it |
| * is executed. The format of this information, and the file or other |
| * output stream to which it is emitted, depends on the host environment. |
| * The virtual machine may ignore this request if it does not support |
| * this feature. The destination of the trace output is system |
| * dependent. |
| * <p> |
| * If the <code>boolean</code> argument is <code>false</code>, this |
| * method causes the virtual machine to stop performing the |
| * detailed instruction trace it is performing. |
| * |
| * @param on <code>true</code> to enable instruction tracing; |
| * <code>false</code> to disable this feature. |
| */ |
| public native void traceInstructions(boolean on); |
| |
| /** |
| * Enables/Disables tracing of method calls. |
| * If the <code>boolean</code> argument is <code>true</code>, this |
| * method suggests that the Java virtual machine emit debugging |
| * information for each method in the virtual machine as it is |
| * called. The format of this information, and the file or other output |
| * stream to which it is emitted, depends on the host environment. The |
| * virtual machine may ignore this request if it does not support |
| * this feature. |
| * <p> |
| * Calling this method with argument false suggests that the |
| * virtual machine cease emitting per-call debugging information. |
| * |
| * @param on <code>true</code> to enable instruction tracing; |
| * <code>false</code> to disable this feature. |
| */ |
| public native void traceMethodCalls(boolean on); |
| |
| /** |
| * Loads the specified filename as a dynamic library. The filename |
| * argument must be a complete path name, |
| * (for example |
| * <code>Runtime.getRuntime().load("/home/avh/lib/libX11.so");</code>). |
| * <p> |
| * First, if there is a security manager, its <code>checkLink</code> |
| * method is called with the <code>filename</code> as its argument. |
| * This may result in a security exception. |
| * <p> |
| * This is similar to the method {@link #loadLibrary(String)}, but it |
| * accepts a general file name as an argument rather than just a library |
| * name, allowing any file of native code to be loaded. |
| * <p> |
| * The method {@link System#load(String)} is the conventional and |
| * convenient means of invoking this method. |
| * |
| * @param filename the file to load. |
| * @exception SecurityException if a security manager exists and its |
| * <code>checkLink</code> method doesn't allow |
| * loading of the specified dynamic library |
| * @exception UnsatisfiedLinkError if the file does not exist. |
| * @exception NullPointerException if <code>filename</code> is |
| * <code>null</code> |
| * @see java.lang.Runtime#getRuntime() |
| * @see java.lang.SecurityException |
| * @see java.lang.SecurityManager#checkLink(java.lang.String) |
| */ |
| public void load(String filename) { |
| load0(System.getCallerClass(), filename); |
| } |
| |
| synchronized void load0(Class fromClass, String filename) { |
| SecurityManager security = System.getSecurityManager(); |
| if (security != null) { |
| security.checkLink(filename); |
| } |
| if (!(new File(filename).isAbsolute())) { |
| throw new UnsatisfiedLinkError( |
| "Expecting an absolute path of the library: " + filename); |
| } |
| ClassLoader.loadLibrary(fromClass, filename, true); |
| } |
| |
| /** |
| * Loads the dynamic library with the specified library name. |
| * A file containing native code is loaded from the local file system |
| * from a place where library files are conventionally obtained. The |
| * details of this process are implementation-dependent. The |
| * mapping from a library name to a specific filename is done in a |
| * system-specific manner. |
| * <p> |
| * First, if there is a security manager, its <code>checkLink</code> |
| * method is called with the <code>libname</code> as its argument. |
| * This may result in a security exception. |
| * <p> |
| * The method {@link System#loadLibrary(String)} is the conventional |
| * and convenient means of invoking this method. If native |
| * methods are to be used in the implementation of a class, a standard |
| * strategy is to put the native code in a library file (call it |
| * <code>LibFile</code>) and then to put a static initializer: |
| * <blockquote><pre> |
| * static { System.loadLibrary("LibFile"); } |
| * </pre></blockquote> |
| * within the class declaration. When the class is loaded and |
| * initialized, the necessary native code implementation for the native |
| * methods will then be loaded as well. |
| * <p> |
| * If this method is called more than once with the same library |
| * name, the second and subsequent calls are ignored. |
| * |
| * @param libname the name of the library. |
| * @exception SecurityException if a security manager exists and its |
| * <code>checkLink</code> method doesn't allow |
| * loading of the specified dynamic library |
| * @exception UnsatisfiedLinkError if the library does not exist. |
| * @exception NullPointerException if <code>libname</code> is |
| * <code>null</code> |
| * @see java.lang.SecurityException |
| * @see java.lang.SecurityManager#checkLink(java.lang.String) |
| */ |
| public void loadLibrary(String libname) { |
| loadLibrary0(System.getCallerClass(), libname); |
| } |
| |
| synchronized void loadLibrary0(Class fromClass, String libname) { |
| SecurityManager security = System.getSecurityManager(); |
| if (security != null) { |
| security.checkLink(libname); |
| } |
| if (libname.indexOf((int)File.separatorChar) != -1) { |
| throw new UnsatisfiedLinkError( |
| "Directory separator should not appear in library name: " + libname); |
| } |
| ClassLoader.loadLibrary(fromClass, libname, false); |
| } |
| |
| /** |
| * Creates a localized version of an input stream. This method takes |
| * an <code>InputStream</code> and returns an <code>InputStream</code> |
| * equivalent to the argument in all respects except that it is |
| * localized: as characters in the local character set are read from |
| * the stream, they are automatically converted from the local |
| * character set to Unicode. |
| * <p> |
| * If the argument is already a localized stream, it may be returned |
| * as the result. |
| * |
| * @param in InputStream to localize |
| * @return a localized input stream |
| * @see java.io.InputStream |
| * @see java.io.BufferedReader#BufferedReader(java.io.Reader) |
| * @see java.io.InputStreamReader#InputStreamReader(java.io.InputStream) |
| * @deprecated As of JDK 1.1, the preferred way to translate a byte |
| * stream in the local encoding into a character stream in Unicode is via |
| * the <code>InputStreamReader</code> and <code>BufferedReader</code> |
| * classes. |
| */ |
| @Deprecated |
| public InputStream getLocalizedInputStream(InputStream in) { |
| return in; |
| } |
| |
| /** |
| * Creates a localized version of an output stream. This method |
| * takes an <code>OutputStream</code> and returns an |
| * <code>OutputStream</code> equivalent to the argument in all respects |
| * except that it is localized: as Unicode characters are written to |
| * the stream, they are automatically converted to the local |
| * character set. |
| * <p> |
| * If the argument is already a localized stream, it may be returned |
| * as the result. |
| * |
| * @deprecated As of JDK 1.1, the preferred way to translate a |
| * Unicode character stream into a byte stream in the local encoding is via |
| * the <code>OutputStreamWriter</code>, <code>BufferedWriter</code>, and |
| * <code>PrintWriter</code> classes. |
| * |
| * @param out OutputStream to localize |
| * @return a localized output stream |
| * @see java.io.OutputStream |
| * @see java.io.BufferedWriter#BufferedWriter(java.io.Writer) |
| * @see java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream) |
| * @see java.io.PrintWriter#PrintWriter(java.io.OutputStream) |
| */ |
| @Deprecated |
| public OutputStream getLocalizedOutputStream(OutputStream out) { |
| return out; |
| } |
| |
| } |
