/* * Copyright (c) 1994, 2010, 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.Properties; import java.util.PropertyPermission; import java.util.StringTokenizer; import java.security.AccessController; import java.security.PrivilegedAction; import java.security.AllPermission; import java.nio.channels.Channel; import java.nio.channels.spi.SelectorProvider; import sun.nio.ch.Interruptible; import sun.reflect.Reflection; import sun.security.util.SecurityConstants; import sun.reflect.annotation.AnnotationType; /** * The System class contains several useful class fields * and methods. It cannot be instantiated. * *

Among the facilities provided by the System class * are standard input, standard output, and error output streams; * access to externally defined properties and environment * variables; a means of loading files and libraries; and a utility * method for quickly copying a portion of an array. * * @author unascribed * @since JDK1.0 */ public final class System { /* register the natives via the static initializer. * * VM will invoke the initializeSystemClass method to complete * the initialization for this class separated from clinit. * Note that to use properties set by the VM, see the constraints * described in the initializeSystemClass method. */ private static native void registerNatives(); static { registerNatives(); } /** Don't let anyone instantiate this class */ private System() { } /** * The "standard" input stream. This stream is already * open and ready to supply input data. Typically this stream * corresponds to keyboard input or another input source specified by * the host environment or user. */ public final static InputStream in = null; /** * The "standard" output stream. This stream is already * open and ready to accept output data. Typically this stream * corresponds to display output or another output destination * specified by the host environment or user. *

* For simple stand-alone Java applications, a typical way to write * a line of output data is: * 

     *     System.out.println(data)
     *
*

* See the println methods in class PrintStream. * * @see java.io.PrintStream#println() * @see java.io.PrintStream#println(boolean) * @see java.io.PrintStream#println(char) * @see java.io.PrintStream#println(char[]) * @see java.io.PrintStream#println(double) * @see java.io.PrintStream#println(float) * @see java.io.PrintStream#println(int) * @see java.io.PrintStream#println(long) * @see java.io.PrintStream#println(java.lang.Object) * @see java.io.PrintStream#println(java.lang.String) */ public final static PrintStream out = null; /** * The "standard" error output stream. This stream is already * open and ready to accept output data. *

* Typically this stream corresponds to display output or another * output destination specified by the host environment or user. By * convention, this output stream is used to display error messages * or other information that should come to the immediate attention * of a user even if the principal output stream, the value of the * variable out, has been redirected to a file or other * destination that is typically not continuously monitored. */ public final static PrintStream err = null; /* The security manager for the system. */ private static volatile SecurityManager security = null; /** * Reassigns the "standard" input stream. * *

First, if there is a security manager, its checkPermission * method is called with a RuntimePermission("setIO") permission * to see if it's ok to reassign the "standard" input stream. *

* * @param in the new standard input stream. * * @throws SecurityException * if a security manager exists and its * checkPermission method doesn't allow * reassigning of the standard input stream. * * @see SecurityManager#checkPermission * @see java.lang.RuntimePermission * * @since JDK1.1 */ public static void setIn(InputStream in) { checkIO(); setIn0(in); } /** * Reassigns the "standard" output stream. * *

First, if there is a security manager, its checkPermission * method is called with a RuntimePermission("setIO") permission * to see if it's ok to reassign the "standard" output stream. * * @param out the new standard output stream * * @throws SecurityException * if a security manager exists and its * checkPermission method doesn't allow * reassigning of the standard output stream. * * @see SecurityManager#checkPermission * @see java.lang.RuntimePermission * * @since JDK1.1 */ public static void setOut(PrintStream out) { checkIO(); setOut0(out); } /** * Reassigns the "standard" error output stream. * *

First, if there is a security manager, its checkPermission * method is called with a RuntimePermission("setIO") permission * to see if it's ok to reassign the "standard" error output stream. * * @param err the new standard error output stream. * * @throws SecurityException * if a security manager exists and its * checkPermission method doesn't allow * reassigning of the standard error output stream. * * @see SecurityManager#checkPermission * @see java.lang.RuntimePermission * * @since JDK1.1 */ public static void setErr(PrintStream err) { checkIO(); setErr0(err); } private static volatile Console cons = null; /** * Returns the unique {@link java.io.Console Console} object associated * with the current Java virtual machine, if any. * * @return The system console, if any, otherwise null. * * @since 1.6 */ public static Console console() { if (cons == null) { synchronized (System.class) { cons = sun.misc.SharedSecrets.getJavaIOAccess().console(); } } return cons; } /** * Returns the channel inherited from the entity that created this * Java virtual machine. * *

This method returns the channel obtained by invoking the * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel * inheritedChannel} method of the system-wide default * {@link java.nio.channels.spi.SelectorProvider} object.

* *

In addition to the network-oriented channels described in * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel * inheritedChannel}, this method may return other kinds of * channels in the future. * * @return The inherited channel, if any, otherwise null. * * @throws IOException * If an I/O error occurs * * @throws SecurityException * If a security manager is present and it does not * permit access to the channel. * * @since 1.5 */ public static Channel inheritedChannel() throws IOException { return SelectorProvider.provider().inheritedChannel(); } private static void checkIO() { SecurityManager sm = getSecurityManager(); if (sm != null) { sm.checkPermission(new RuntimePermission("setIO")); } } private static native void setIn0(InputStream in); private static native void setOut0(PrintStream out); private static native void setErr0(PrintStream err); /** * Sets the System security. * *

If there is a security manager already installed, this method first * calls the security manager's checkPermission method * with a RuntimePermission("setSecurityManager") * permission to ensure it's ok to replace the existing * security manager. * This may result in throwing a SecurityException. * *

Otherwise, the argument is established as the current * security manager. If the argument is null and no * security manager has been established, then no action is taken and * the method simply returns. * * @param s the security manager. * @exception SecurityException if the security manager has already * been set and its checkPermission method * doesn't allow it to be replaced. * @see #getSecurityManager * @see SecurityManager#checkPermission * @see java.lang.RuntimePermission */ public static void setSecurityManager(final SecurityManager s) { try { s.checkPackageAccess("java.lang"); } catch (Exception e) { // no-op } setSecurityManager0(s); } private static synchronized void setSecurityManager0(final SecurityManager s) { SecurityManager sm = getSecurityManager(); if (sm != null) { // ask the currently installed security manager if we // can replace it. sm.checkPermission(new RuntimePermission ("setSecurityManager")); } if ((s != null) && (s.getClass().getClassLoader() != null)) { // New security manager class is not on bootstrap classpath. // Cause policy to get initialized before we install the new // security manager, in order to prevent infinite loops when // trying to initialize the policy (which usually involves // accessing some security and/or system properties, which in turn // calls the installed security manager's checkPermission method // which will loop infinitely if there is a non-system class // (in this case: the new security manager class) on the stack). AccessController.doPrivileged(new PrivilegedAction() { public Object run() { s.getClass().getProtectionDomain().implies (SecurityConstants.ALL_PERMISSION); return null; } }); } security = s; } /** * Gets the system security interface. * * @return if a security manager has already been established for the * current application, then that security manager is returned; * otherwise, null is returned. * @see #setSecurityManager */ public static SecurityManager getSecurityManager() { return security; } /** * Returns the current time in milliseconds. Note that * while the unit of time of the return value is a millisecond, * the granularity of the value depends on the underlying * operating system and may be larger. For example, many * operating systems measure time in units of tens of * milliseconds. * *

See the description of the class Date for * a discussion of slight discrepancies that may arise between * "computer time" and coordinated universal time (UTC). * * @return the difference, measured in milliseconds, between * the current time and midnight, January 1, 1970 UTC. * @see java.util.Date */ public static native long currentTimeMillis(); /** * Returns the current value of the running Java Virtual Machine's * high-resolution time source, in nanoseconds. * *

This method can only be used to measure elapsed time and is * not related to any other notion of system or wall-clock time. * The value returned represents nanoseconds since some fixed but * arbitrary origin time (perhaps in the future, so values * may be negative). The same origin is used by all invocations of * this method in an instance of a Java virtual machine; other * virtual machine instances are likely to use a different origin. * *

This method provides nanosecond precision, but not necessarily * nanosecond resolution (that is, how frequently the value changes) * - no guarantees are made except that the resolution is at least as * good as that of {@link #currentTimeMillis()}. * *

Differences in successive calls that span greater than * approximately 292 years (263 nanoseconds) will not * correctly compute elapsed time due to numerical overflow. * *

The values returned by this method become meaningful only when * the difference between two such values, obtained within the same * instance of a Java virtual machine, is computed. * *

For example, to measure how long some code takes to execute: * 

 {@code
     * long startTime = System.nanoTime();
     * // ... the code being measured ...
     * long estimatedTime = System.nanoTime() - startTime;}
* *

To compare two nanoTime values * 

 {@code
     * long t0 = System.nanoTime();
     * ...
     * long t1 = System.nanoTime();}
* * one should use {@code t1 - t0 < 0}, not {@code t1 < t0}, * because of the possibility of numerical overflow. * * @return the current value of the running Java Virtual Machine's * high-resolution time source, in nanoseconds * @since 1.5 */ public static native long nanoTime(); /** * Copies an array from the specified source array, beginning at the * specified position, to the specified position of the destination array. * A subsequence of array components are copied from the source * array referenced by src to the destination array * referenced by dest. The number of components copied is * equal to the length argument. The components at * positions srcPos through * srcPos+length-1 in the source array are copied into * positions destPos through * destPos+length-1, respectively, of the destination * array. *

* If the src and dest arguments refer to the * same array object, then the copying is performed as if the * components at positions srcPos through * srcPos+length-1 were first copied to a temporary * array with length components and then the contents of * the temporary array were copied into positions * destPos through destPos+length-1 of the * destination array. *

* If dest is null, then a * NullPointerException is thrown. *

* If src is null, then a * NullPointerException is thrown and the destination * array is not modified. *

* Otherwise, if any of the following is true, an * ArrayStoreException is thrown and the destination is * not modified: *

*

* Otherwise, if any of the following is true, an * IndexOutOfBoundsException is * thrown and the destination is not modified: *

*

* Otherwise, if any actual component of the source array from * position srcPos through * srcPos+length-1 cannot be converted to the component * type of the destination array by assignment conversion, an * ArrayStoreException is thrown. In this case, let * k be the smallest nonnegative integer less than * length such that src[srcPos+k] * cannot be converted to the component type of the destination * array; when the exception is thrown, source array components from * positions srcPos through * srcPos+k-1 * will already have been copied to destination array positions * destPos through * destPos+k-1 and no other * positions of the destination array will have been modified. * (Because of the restrictions already itemized, this * paragraph effectively applies only to the situation where both * arrays have component types that are reference types.) * * @param src the source array. * @param srcPos starting position in the source array. * @param dest the destination array. * @param destPos starting position in the destination data. * @param length the number of array elements to be copied. * @exception IndexOutOfBoundsException if copying would cause * access of data outside array bounds. * @exception ArrayStoreException if an element in the src * array could not be stored into the dest array * because of a type mismatch. * @exception NullPointerException if either src or * dest is null. */ public static native void arraycopy(Object src, int srcPos, Object dest, int destPos, int length); /** * Returns the same hash code for the given object as * would be returned by the default method hashCode(), * whether or not the given object's class overrides * hashCode(). * The hash code for the null reference is zero. * * @param x object for which the hashCode is to be calculated * @return the hashCode * @since JDK1.1 */ public static native int identityHashCode(Object x); /** * System properties. The following properties are guaranteed to be defined: *

*
java.version
Java version number *
java.vendor
Java vendor specific string *
java.vendor.url
Java vendor URL *
java.home
Java installation directory *
java.class.version
Java class version number *
java.class.path
Java classpath *
os.name
Operating System Name *
os.arch
Operating System Architecture *
os.version
Operating System Version *
file.separator
File separator ("/" on Unix) *
path.separator
Path separator (":" on Unix) *
line.separator
Line separator ("\n" on Unix) *
user.name
User account name *
user.home
User home directory *
user.dir
User's current working directory *
*/ private static Properties props; private static native Properties initProperties(Properties props); /** * Determines the current system properties. *

* First, if there is a security manager, its * checkPropertiesAccess method is called with no * arguments. This may result in a security exception. *

* The current set of system properties for use by the * {@link #getProperty(String)} method is returned as a * Properties object. If there is no current set of * system properties, a set of system properties is first created and * initialized. This set of system properties always includes values * for the following keys: * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
KeyDescription of Associated Value
java.versionJava Runtime Environment version
java.vendorJava Runtime Environment vendor
java.vendor.urlJava vendor URL
java.homeJava installation directory
java.vm.specification.versionJava Virtual Machine specification version
java.vm.specification.vendorJava Virtual Machine specification vendor
java.vm.specification.nameJava Virtual Machine specification name
java.vm.versionJava Virtual Machine implementation version
java.vm.vendorJava Virtual Machine implementation vendor
java.vm.nameJava Virtual Machine implementation name
java.specification.versionJava Runtime Environment specification version
java.specification.vendorJava Runtime Environment specification vendor
java.specification.nameJava Runtime Environment specification name
java.class.versionJava class format version number
java.class.pathJava class path
java.library.pathList of paths to search when loading libraries
java.io.tmpdirDefault temp file path
java.compilerName of JIT compiler to use
java.ext.dirsPath of extension directory or directories
os.nameOperating system name
os.archOperating system architecture
os.versionOperating system version
file.separatorFile separator ("/" on UNIX)
path.separatorPath separator (":" on UNIX)
line.separatorLine separator ("\n" on UNIX)
user.nameUser's account name
user.homeUser's home directory
user.dirUser's current working directory
*

* Multiple paths in a system property value are separated by the path * separator character of the platform. *

* Note that even if the security manager does not permit the * getProperties operation, it may choose to permit the * {@link #getProperty(String)} operation. * * @return the system properties * @exception SecurityException if a security manager exists and its * checkPropertiesAccess method doesn't allow access * to the system properties. * @see #setProperties * @see java.lang.SecurityException * @see java.lang.SecurityManager#checkPropertiesAccess() * @see java.util.Properties */ public static Properties getProperties() { SecurityManager sm = getSecurityManager(); if (sm != null) { sm.checkPropertiesAccess(); } return props; } /** * Returns the system-dependent line separator string. It always * returns the same value - the initial value of the {@linkplain * #getProperty(String) system property} {@code line.separator}. * *

On UNIX systems, it returns {@code "\n"}; on Microsoft * Windows systems it returns {@code "\r\n"}. */ public static String lineSeparator() { return lineSeparator; } private static String lineSeparator; /** * Sets the system properties to the Properties * argument. *

* First, if there is a security manager, its * checkPropertiesAccess method is called with no * arguments. This may result in a security exception. *

* The argument becomes the current set of system properties for use * by the {@link #getProperty(String)} method. If the argument is * null, then the current set of system properties is * forgotten. * * @param props the new system properties. * @exception SecurityException if a security manager exists and its * checkPropertiesAccess method doesn't allow access * to the system properties. * @see #getProperties * @see java.util.Properties * @see java.lang.SecurityException * @see java.lang.SecurityManager#checkPropertiesAccess() */ public static void setProperties(Properties props) { SecurityManager sm = getSecurityManager(); if (sm != null) { sm.checkPropertiesAccess(); } if (props == null) { props = new Properties(); initProperties(props); } System.props = props; } /** * Gets the system property indicated by the specified key. *

* First, if there is a security manager, its * checkPropertyAccess method is called with the key as * its argument. This may result in a SecurityException. *

* If there is no current set of system properties, a set of system * properties is first created and initialized in the same manner as * for the getProperties method. * * @param key the name of the system property. * @return the string value of the system property, * or null if there is no property with that key. * * @exception SecurityException if a security manager exists and its * checkPropertyAccess method doesn't allow * access to the specified system property. * @exception NullPointerException if key is * null. * @exception IllegalArgumentException if key is empty. * @see #setProperty * @see java.lang.SecurityException * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String) * @see java.lang.System#getProperties() */ public static String getProperty(String key) { checkKey(key); SecurityManager sm = getSecurityManager(); if (sm != null) { sm.checkPropertyAccess(key); } return props.getProperty(key); } /** * Gets the system property indicated by the specified key. *

* First, if there is a security manager, its * checkPropertyAccess method is called with the * key as its argument. *

* If there is no current set of system properties, a set of system * properties is first created and initialized in the same manner as * for the getProperties method. * * @param key the name of the system property. * @param def a default value. * @return the string value of the system property, * or the default value if there is no property with that key. * * @exception SecurityException if a security manager exists and its * checkPropertyAccess method doesn't allow * access to the specified system property. * @exception NullPointerException if key is * null. * @exception IllegalArgumentException if key is empty. * @see #setProperty * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String) * @see java.lang.System#getProperties() */ public static String getProperty(String key, String def) { checkKey(key); SecurityManager sm = getSecurityManager(); if (sm != null) { sm.checkPropertyAccess(key); } return props.getProperty(key, def); } /** * Sets the system property indicated by the specified key. *

* First, if a security manager exists, its * SecurityManager.checkPermission method * is called with a PropertyPermission(key, "write") * permission. This may result in a SecurityException being thrown. * If no exception is thrown, the specified property is set to the given * value. *

* * @param key the name of the system property. * @param value the value of the system property. * @return the previous value of the system property, * or null if it did not have one. * * @exception SecurityException if a security manager exists and its * checkPermission method doesn't allow * setting of the specified property. * @exception NullPointerException if key or * value is null. * @exception IllegalArgumentException if key is empty. * @see #getProperty * @see java.lang.System#getProperty(java.lang.String) * @see java.lang.System#getProperty(java.lang.String, java.lang.String) * @see java.util.PropertyPermission * @see SecurityManager#checkPermission * @since 1.2 */ public static String setProperty(String key, String value) { checkKey(key); SecurityManager sm = getSecurityManager(); if (sm != null) { sm.checkPermission(new PropertyPermission(key, SecurityConstants.PROPERTY_WRITE_ACTION)); } return (String) props.setProperty(key, value); } /** * Removes the system property indicated by the specified key. *

* First, if a security manager exists, its * SecurityManager.checkPermission method * is called with a PropertyPermission(key, "write") * permission. This may result in a SecurityException being thrown. * If no exception is thrown, the specified property is removed. *

* * @param key the name of the system property to be removed. * @return the previous string value of the system property, * or null if there was no property with that key. * * @exception SecurityException if a security manager exists and its * checkPropertyAccess method doesn't allow * access to the specified system property. * @exception NullPointerException if key is * null. * @exception IllegalArgumentException if key is empty. * @see #getProperty * @see #setProperty * @see java.util.Properties * @see java.lang.SecurityException * @see java.lang.SecurityManager#checkPropertiesAccess() * @since 1.5 */ public static String clearProperty(String key) { checkKey(key); SecurityManager sm = getSecurityManager(); if (sm != null) { sm.checkPermission(new PropertyPermission(key, "write")); } return (String) props.remove(key); } private static void checkKey(String key) { if (key == null) { throw new NullPointerException("key can't be null"); } if (key.equals("")) { throw new IllegalArgumentException("key can't be empty"); } } /** * Gets the value of the specified environment variable. An * environment variable is a system-dependent external named * value. * *

If a security manager exists, its * {@link SecurityManager#checkPermission checkPermission} * method is called with a * {@link RuntimePermission}("getenv."+name) * permission. This may result in a {@link SecurityException} * being thrown. If no exception is thrown the value of the * variable name is returned. * *

System * properties and environment variables are both * conceptually mappings between names and values. Both * mechanisms can be used to pass user-defined information to a * Java process. Environment variables have a more global effect, * because they are visible to all descendants of the process * which defines them, not just the immediate Java subprocess. * They can have subtly different semantics, such as case * insensitivity, on different operating systems. For these * reasons, environment variables are more likely to have * unintended side effects. It is best to use system properties * where possible. Environment variables should be used when a * global effect is desired, or when an external system interface * requires an environment variable (such as PATH). * *

On UNIX systems the alphabetic case of name is * typically significant, while on Microsoft Windows systems it is * typically not. For example, the expression * System.getenv("FOO").equals(System.getenv("foo")) * is likely to be true on Microsoft Windows. * * @param name the name of the environment variable * @return the string value of the variable, or null * if the variable is not defined in the system environment * @throws NullPointerException if name is null * @throws SecurityException * if a security manager exists and its * {@link SecurityManager#checkPermission checkPermission} * method doesn't allow access to the environment variable * name * @see #getenv() * @see ProcessBuilder#environment() */ public static String getenv(String name) { SecurityManager sm = getSecurityManager(); if (sm != null) { sm.checkPermission(new RuntimePermission("getenv."+name)); } return ProcessEnvironment.getenv(name); } /** * Returns an unmodifiable string map view of the current system environment. * The environment is a system-dependent mapping from names to * values which is passed from parent to child processes. * *

If the system does not support environment variables, an * empty map is returned. * *

The returned map will never contain null keys or values. * Attempting to query the presence of a null key or value will * throw a {@link NullPointerException}. Attempting to query * the presence of a key or value which is not of type * {@link String} will throw a {@link ClassCastException}. * *

The returned map and its collection views may not obey the * general contract of the {@link Object#equals} and * {@link Object#hashCode} methods. * *

The returned map is typically case-sensitive on all platforms. * *

If a security manager exists, its * {@link SecurityManager#checkPermission checkPermission} * method is called with a * {@link RuntimePermission}("getenv.*") * permission. This may result in a {@link SecurityException} being * thrown. * *

When passing information to a Java subprocess, * system properties * are generally preferred over environment variables. * * @return the environment as a map of variable names to values * @throws SecurityException * if a security manager exists and its * {@link SecurityManager#checkPermission checkPermission} * method doesn't allow access to the process environment * @see #getenv(String) * @see ProcessBuilder#environment() * @since 1.5 */ public static java.util.Map getenv() { SecurityManager sm = getSecurityManager(); if (sm != null) { sm.checkPermission(new RuntimePermission("getenv.*")); } return ProcessEnvironment.getenv(); } /** * Terminates the currently running Java Virtual Machine. The * argument serves as a status code; by convention, a nonzero status * code indicates abnormal termination. *

* This method calls the exit method in class * Runtime. This method never returns normally. *

* The call System.exit(n) is effectively equivalent to * the call: * 

     * Runtime.getRuntime().exit(n)
     *
* * @param status exit status. * @throws SecurityException * if a security manager exists and its checkExit * method doesn't allow exit with the specified status. * @see java.lang.Runtime#exit(int) */ public static void exit(int status) { Runtime.getRuntime().exit(status); } /** * Runs the garbage collector. *

* Calling the gc 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 Java Virtual * Machine has made a best effort to reclaim space from all discarded * objects. *

* The call System.gc() is effectively equivalent to the * call: * 

     * Runtime.getRuntime().gc()
     *
* * @see java.lang.Runtime#gc() */ public static void gc() { Runtime.getRuntime().gc(); } /** * Runs the finalization methods of any objects pending finalization. *

* Calling this method suggests that the Java Virtual Machine expend * effort toward running the finalize methods of objects * that have been found to be discarded but whose finalize * methods have not yet been run. When control returns from the * method call, the Java Virtual Machine has made a best effort to * complete all outstanding finalizations. *

* The call System.runFinalization() is effectively * equivalent to the call: * 

     * Runtime.getRuntime().runFinalization()
     *
* * @see java.lang.Runtime#runFinalization() */ public static void runFinalization() { Runtime.getRuntime().runFinalization(); } /** * 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. * *

If there is a security manager, * its checkExit method is first called * with 0 as its argument to ensure the exit is allowed. * This could result in a SecurityException. * * @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. * @param value indicating enabling or disabling of finalization * @throws SecurityException * if a security manager exists and its checkExit * 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) { Runtime.getRuntime().runFinalizersOnExit(value); } /** * Loads a code file with the specified filename from the local file * system as a dynamic library. The filename * argument must be a complete path name. *

* The call System.load(name) is effectively equivalent * to the call: * 

     * Runtime.getRuntime().load(name)
     *
* * @param filename the file to load. * @exception SecurityException if a security manager exists and its * checkLink method doesn't allow * loading of the specified dynamic library * @exception UnsatisfiedLinkError if the file does not exist. * @exception NullPointerException if filename is * null * @see java.lang.Runtime#load(java.lang.String) * @see java.lang.SecurityManager#checkLink(java.lang.String) */ public static void load(String filename) { Runtime.getRuntime().load0(getCallerClass(), filename); } /** * Loads the system library specified by the libname * argument. The manner in which a library name is mapped to the * actual system library is system dependent. *

* The call System.loadLibrary(name) is effectively * equivalent to the call * 

     * Runtime.getRuntime().loadLibrary(name)
     *
* * @param libname the name of the library. * @exception SecurityException if a security manager exists and its * checkLink method doesn't allow * loading of the specified dynamic library * @exception UnsatisfiedLinkError if the library does not exist. * @exception NullPointerException if libname is * null * @see java.lang.Runtime#loadLibrary(java.lang.String) * @see java.lang.SecurityManager#checkLink(java.lang.String) */ public static void loadLibrary(String libname) { Runtime.getRuntime().loadLibrary0(getCallerClass(), libname); } /** * Maps a library name into a platform-specific string representing * a native library. * * @param libname the name of the library. * @return a platform-dependent native library name. * @exception NullPointerException if libname is * null * @see java.lang.System#loadLibrary(java.lang.String) * @see java.lang.ClassLoader#findLibrary(java.lang.String) * @since 1.2 */ public static native String mapLibraryName(String libname); /** * Initialize the system class. Called after thread initialization. */ private static void initializeSystemClass() { // There are certain system configurations that may be controlled by // VM options such as the maximum amount of direct memory and // Integer cache size used to support the object identity semantics // of autoboxing. Typically, the library will obtain these values // from the properties set by the VM. If the properties are for // internal implementation use only, these properties should be // removed from the system properties. // // See java.lang.Integer.IntegerCache and the // sun.misc.VM.saveAndRemoveProperties method for example. props = initSystemProperties(); lineSeparator = props.getProperty("line.separator"); sun.misc.Version.init(); FileInputStream fdIn = new FileInputStream(FileDescriptor.in); FileOutputStream fdOut = new FileOutputStream(FileDescriptor.out); FileOutputStream fdErr = new FileOutputStream(FileDescriptor.err); setIn0(new BufferedInputStream(fdIn)); setOut0(new PrintStream(new BufferedOutputStream(fdOut, 128), true)); setErr0(new PrintStream(new BufferedOutputStream(fdErr, 128), true)); // Load the zip library now in order to keep java.util.zip.ZipFile // from trying to use itself to load this library later. loadLibrary("zip"); // Setup Java signal handlers for HUP, TERM, and INT (where available). Terminator.setup(); // Initialize any miscellenous operating system settings that need to be // set for the class libraries. Currently this is no-op everywhere except // for Windows where the process-wide error mode is set before the java.io // classes are used. sun.misc.VM.initializeOSEnvironment(); // Subsystems that are invoked during initialization can invoke // sun.misc.VM.isBooted() in order to avoid doing things that should // wait until the application class loader has been set up. sun.misc.VM.booted(); // The main thread is not added to its thread group in the same // way as other threads; we must do it ourselves here. Thread current = Thread.currentThread(); current.getThreadGroup().add(current); // register shared secrets setJavaLangAccess(); } private static Properties initSystemProperties() { Properties props = new Properties(); initProperties(props); // initialized by the VM // Save a private copy of the system properties object that // can only be accessed by the internal implementation. Remove // certain system properties that are not intended for public access. sun.misc.VM.saveAndRemoveProperties(props); return props; } private static void setJavaLangAccess() { // Allow privileged classes outside of java.lang sun.misc.SharedSecrets.setJavaLangAccess(new sun.misc.JavaLangAccess(){ public sun.reflect.ConstantPool getConstantPool(Class klass) { return klass.getConstantPool(); } public void setAnnotationType(Class klass, AnnotationType type) { klass.setAnnotationType(type); } public AnnotationType getAnnotationType(Class klass) { return klass.getAnnotationType(); } public > E[] getEnumConstantsShared(Class klass) { return klass.getEnumConstantsShared(); } public void blockedOn(Thread t, Interruptible b) { t.blockedOn(b); } public void registerShutdownHook(int slot, boolean registerShutdownInProgress, Runnable hook) { Shutdown.add(slot, registerShutdownInProgress, hook); } public int getStackTraceDepth(Throwable t) { return t.getStackTraceDepth(); } public StackTraceElement getStackTraceElement(Throwable t, int i) { return t.getStackTraceElement(i); } }); } /* returns the class of the caller. */ static Class getCallerClass() { // NOTE use of more generic Reflection.getCallerClass() return Reflection.getCallerClass(3); } }