java.lang
Class System

java.lang.Object
  |
  +--java.lang.System

public final class System

extends Object

The System class contains several useful class fields and methods. It cannot be instantiated.

Some of the code as well as javadoc in this class was stolen from:

@(#)System.java	1.125 01/12/03

 Copyright 2002 Sun Microsystems, Inc. All rights reserved.
 SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.

Therefore, credit is given to the original author, Arthur van Hoff.

Among the facilities provided by the System class are standard input, standard output, and error output streams; access to externally defined "properties"; a means of loading files and libraries; and a utility method for quickly copying a portion of an array.

Since:

JDK1.0

Version:

1.125, 12/03/01

Author:

Arthur van Hoff

, Matt Murphy (the thief)

See Also:

NewSystem

Field Summary

static java.io.PrintStream	err
static java.io.InputStream	in
static java.io.PrintStream	out
private static java.util.Properties	props System properties.
private static SecurityManager	security

Constructor Summary

private

System() Don't let anyone instantiate this class

Method Summary

static void	arraycopy(Object src, int srcPos, Object dest, int destPos, int length)
private static boolean	calledFromOldSystem()
static long	currentTimeMillis()
static void	exit(int status)
static void	gc()
(package private) static Class	getCallerClass()
static String	getenv(String name)
static java.util.Properties	getProperties()
static String	getProperty(String key)
static String	getProperty(String key, String def)
static SecurityManager	getSecurityManager()
static int	identityHashCode(Object x)
private static void	initializeSystemClass() Initialize the system class.
private static java.util.Properties	initProperties(java.util.Properties props)
static void	load(String filename)
static void	loadLibrary(String libname)
static String	mapLibraryName(String libname)
private static java.io.InputStream	nullInputStream() The following two methods exist because in, out, and err must be initialized to null.
private static java.io.PrintStream	nullPrintStream()
private static void	registerNatives()
static void	runFinalization()
static void	runFinalizersOnExit(boolean value)
static void	setErr(java.io.PrintStream err)
private static void	setErr0(java.io.PrintStream err)
static void	setIn(java.io.InputStream in)
private static void	setIn0(java.io.InputStream in)
static void	setOut(java.io.PrintStream out)
private static void	setOut0(java.io.PrintStream out)
static void	setProperties(java.util.Properties props)
static String	setProperty(String key, String value)
static void	setSecurityManager(SecurityManager s)
private static void	setSecurityManager0(SecurityManager s)

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

in

public static final java.io.InputStream in

See Also:

NewSystem.in

out

public static final java.io.PrintStream out

See Also:

NewSystem.out, PrintStream.println(), PrintStream.println(boolean), PrintStream.println(char), PrintStream.println(char[]), PrintStream.println(double), PrintStream.println(float), PrintStream.println(int), PrintStream.println(long), PrintStream.println(java.lang.Object), PrintStream.println(java.lang.String)

err

public static final java.io.PrintStream err

See Also:

NewSystem.err

security

private static SecurityManager security

props

private static java.util.Properties props

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

Constructor Detail

System

private System()

Don't let anyone instantiate this class

Method Detail

registerNatives

private static void registerNatives()

setIn

public static void setIn(java.io.InputStream in)

See Also:

NewSystem.setIn(InputStream)

setOut

public static void setOut(java.io.PrintStream out)

See Also:

NewSystem.setOut(PrintStream)

setErr

public static void setErr(java.io.PrintStream err)

See Also:

NewSystem.setErr(PrintStream)

setIn0

private static void setIn0(java.io.InputStream in)

setOut0

private static void setOut0(java.io.PrintStream out)

setErr0

private static void setErr0(java.io.PrintStream err)

setSecurityManager

public static void setSecurityManager(SecurityManager s)

See Also:

NewSystem.setSecurityManager(SecurityManager)

setSecurityManager0

private static void setSecurityManager0(SecurityManager s)

getSecurityManager

public static SecurityManager getSecurityManager()

See Also:

NewSystem.getSecurityManager()

currentTimeMillis

public static long currentTimeMillis()

See Also:

OldSystem.currentTimeMillis()

arraycopy

public static void arraycopy(Object src,
                             int srcPos,
                             Object dest,
                             int destPos,
                             int length)

See Also:

OldSystem.arraycopy(Object,int,Object,int,int)

identityHashCode

public static int identityHashCode(Object x)

See Also:

OldSystem.identityHashCode(Object)

initProperties

private static java.util.Properties initProperties(java.util.Properties props)

getProperties

public static java.util.Properties getProperties()

See Also:

NewSystem.getProperties()

setProperties

public static void setProperties(java.util.Properties props)

See Also:

NewSystem.setProperties(Properties)

getProperty

public static String getProperty(String key)

See Also:

NewSystem.getProperty(String)

getProperty

public static String getProperty(String key,
                                 String def)

See Also:

NewSystem.getProperty(String)

setProperty

public static String setProperty(String key,
                                 String value)

See Also:

NewSystem.setProperty(String,String)

getenv

public static String getenv(String name)

See Also:

OldSystem.getenv(String)

exit

public static void exit(int status)

See Also:

NewSystem.exit(int)

gc

public static void gc()

See Also:

OldSystem.gc()

runFinalization

public static void runFinalization()

See Also:

OldSystem.runFinalization()

runFinalizersOnExit

public static void runFinalizersOnExit(boolean value)

See Also:

OldSystem.runFinalizersOnExit(boolean)

load

public static void load(String filename)

See Also:

OldSystem.load(String)

loadLibrary

public static void loadLibrary(String libname)

See Also:

OldSystem.loadLibrary(String)

mapLibraryName

public static String mapLibraryName(String libname)

See Also:

OldSystem.mapLibraryName(String)

nullInputStream

private static java.io.InputStream nullInputStream()
                                            throws NullPointerException

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().

NullPointerException

nullPrintStream

private static java.io.PrintStream nullPrintStream()
                                            throws NullPointerException

NullPointerException

initializeSystemClass

private static void initializeSystemClass()

Initialize the system class. Called after thread initialization.

getCallerClass

static Class getCallerClass()

calledFromOldSystem

private static boolean calledFromOldSystem()