/*
* @(#)System.java 1.149 04/06/02
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
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.net.InetAddressCachePolicy;
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
* @version 1.149, 06/02/04
* @since JDK1.0
*/
public final class System {
/* First thing---register the natives */
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 = nullInputStream();
/**
* 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 = nullPrintStream();
/**
* 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 = nullPrintStream();
/* The security manager for the system.
*/
private static 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);
}
/**
* 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() { if (security != null) security.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) {
if (security != null) {
// ask the currently installed security manager if we
// can replace it.
security.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;
InetAddressCachePolicy.setIfNotSet(InetAddressCachePolicy.FOREVER);
}
/**
* 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 most precise available system
* timer, 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 time (perhaps in the future, so values may be * negative). This method provides nanosecond precision, but not * necessarily nanosecond accuracy. No guarantees are made about * how frequently values change. Differences in successive calls * that span greater than approximately 292 years (263 * nanoseconds) will not accurately compute elapsed time due to * numerical overflow. * *
For example, to measure how long some code takes to execute: *
* long startTime = System.nanoTime(); * // ... the code being measured ... * long estimatedTime = System.nanoTime() - startTime; ** * @return The current value of the system timer, 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:
*
src
argument refers to an object that is not an
* array.
* dest
argument refers to an object that is not an
* array.
* src
argument and dest
argument refer
* to arrays whose component types are different primitive types.
* src
argument refers to an array with a primitive
* component type and the dest
argument refers to an array
* with a reference component type.
* src
argument refers to an array with a reference
* component type and the dest
argument refers to an array
* with a primitive component type.
*
* Otherwise, if any of the following is true, an
* IndexOutOfBoundsException
is
* thrown and the destination is not modified:
*
srcPos
argument is negative.
* destPos
argument is negative.
* length
argument is negative.
* srcPos+length
is greater than
* src.length
, the length of the source array.
* destPos+length
is greater than
* dest.length
, the length of the destination array.
*
* 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:
*
* 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:
*
Key | *Description of Associated Value |
---|---|
java.version |
* Java Runtime Environment version |
java.vendor |
* Java Runtime Environment vendor | java.vendor.url |
* Java vendor URL | *
java.home |
* Java installation directory |
java.vm.specification.version |
* Java Virtual Machine specification version |
java.vm.specification.vendor |
* Java Virtual Machine specification vendor |
java.vm.specification.name |
* Java Virtual Machine specification name |
java.vm.version |
* Java Virtual Machine implementation version |
java.vm.vendor |
* Java Virtual Machine implementation vendor |
java.vm.name |
* Java Virtual Machine implementation name |
java.specification.version |
* Java Runtime Environment specification version |
java.specification.vendor |
* Java Runtime Environment specification vendor |
java.specification.name |
* Java Runtime Environment specification name |
java.class.version |
* Java class format version number |
java.class.path |
* Java class path |
java.library.path |
* List of paths to search when loading libraries |
java.io.tmpdir |
* Default temp file path |
java.compiler |
* Name of JIT compiler to use |
java.ext.dirs |
* Path of extension directory or directories |
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's account name |
user.home |
* User's home directory |
user.dir |
* User'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() {
if (security != null) {
security.checkPropertiesAccess();
}
return props;
}
/**
* 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) {
if (security != null) {
security.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);
if (security != null) {
security.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);
if (security != null) {
security.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);
if (security != null)
security.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);
if (security != null)
security.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 On UNIX systems the alphabetic case of 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
* 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
* This method calls the
* The call
* Calling the
* The call
* Calling this method suggests that the Java Virtual Machine expend
* effort toward running the
* The call If there is a security manager,
* its
* The call
* The call PATH
).
*
* 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) {
if (security != null)
security.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.
*
* {@link RuntimePermission}("getenv.*")
* permission. This may result in a {@link SecurityException} being
* thrown.
*
* exit
method in class
* Runtime
. This method never returns normally.
* System.exit(n)
is effectively equivalent to
* the call:
*
*
* @param status exit status.
* @throws SecurityException
* if a security manager exists and its
* Runtime.getRuntime().exit(n)
*
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.
* 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.
* System.gc()
is effectively equivalent to the
* call:
*
*
* @see java.lang.Runtime#gc()
*/
public static void gc() {
Runtime.getRuntime().gc();
}
/**
* Runs the finalization methods of any objects pending finalization.
*
* Runtime.getRuntime().gc()
*
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.
* System.runFinalization()
is effectively
* equivalent to the call:
*
*
* @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.
*
*
* Runtime.getRuntime().runFinalization()
*
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.
* System.load(name)
is effectively equivalent
* to the call:
*
*
* @param filename the file to load.
* @exception SecurityException if a security manager exists and its
*
* Runtime.getRuntime().load(name)
*
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.
* System.loadLibrary(name)
is effectively
* equivalent to the call
*
*
* @param libname the name of the library.
* @exception SecurityException if a security manager exists and its
*
* Runtime.getRuntime().loadLibrary(name)
*
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);
/**
* The following two methods exist because in, out, and err must be
* initialized to null. The compiler, however, cannot be permitted to
* inline access to them, since they are later set to more sensible values
* by initializeSystemClass().
*/
private static InputStream nullInputStream() throws NullPointerException {
if (currentTimeMillis() > 0)
return null;
throw new NullPointerException();
}
private static PrintStream nullPrintStream() throws NullPointerException {
if (currentTimeMillis() > 0)
return null;
throw new NullPointerException();
}
/**
* Initialize the system class. Called after thread initialization.
*/
private static void initializeSystemClass() {
props = new Properties();
initProperties(props);
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");
// Currently File.deleteOnExit is built on JVM_Exit, which is a
// separate mechanism from shutdown hooks. Unfortunately in order to
// work properly JVM_Exit implicitly requires that Java signal
// handlers be set up for HUP, TERM, and INT (where available). If
// File.deleteOnExit were implemented in terms of shutdown hooks this
// call to Terminator.setup() could be removed.
Terminator.setup();
// Set the maximum amount of direct memory. This value is controlled
// by the vm option -XX:MaxDirectMemorySize=