THE PACKAGE JAVA.LANG

java.lang.System

20.18

20.18 The Class

java.lang.System

The

System

 class contains a number of useful class variables and class methods.

It cannot be instantiated. Among the facilities provided by the

System

 class are

standard input, 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.

public final class System {

public static InputStream in;

public static PrintStream out;

public static PrintStream err;

public static SecurityManager getSecurityManager();

public static void setSecurityManager(SecurityManager s)

throws SecurityException;

public static long currentTimeMillis();

public static Properties getProperties()

throws SecurityException;

public static void setProperties(Properties props)

throws SecurityException;

public static String getProperty(String key)

throws SecurityException;

public static String getProperty(String key, String defaults)

throws SecurityException;

public static void exit(int status) throws SecurityException;

public static void gc();

public static void runFinalization();

public static void load(String filename)

throws SecurityException, UnsatisfiedLinkError;

public static void loadLibrary(String libname)

throws SecurityException, UnsatisfiedLinkError;

public static void arraycopy(Object src, int srcOffset,

Object dst, int dstOffset, int length)

throws NullPointerException,

ArrayStoreException, IndexOutOfBoundsException;

}

20.18.1

public static InputStream in;

The initial value of this variable is a  standard  input stream, already open and

ready to supply input data. Typically, this corresponds to keyboard input or

another input source specified by the host environment or user. Note that this field

is not

final

, so its value may be updated if necessary.

579