We are using System.out.print() function in our daily programming to print data or debug code. The System class contains several useful class fields and methods. System class is final and all methods under System are static. System class provides facilities i.e. standard input, standard output, and error output streams, access to external “properties”, loading files and libraries, a utility method for quickly copying a portion of an array etc.
Variable Index:
  • in: The “standard” input stream.
  • out: The “standard” output stream.
  • error: The “standard” error output stream.
Variable Method:
  • arraycopy(Object, int, Object, int, int): Copies an array from the specified source array, beginning at the specified position, to the specified position of the destination array.
  • currentTimeMillis(): Returns the current time in milliseconds.
  • exit(int): Terminates the currently running Java Virtual Machine.
  • gc(): Runs the garbage collector.
  • getenv(String): Gets an environment variable. Deprecated.
  • getProperties(): Determines the current system properties.
  • getProperty(String): Gets the system property indicated by the specified key.
  • getProperty(String, String): Gets the system property indicated by the specified key.
  • getSecurityManager(): Gets the system security interface.
  • identityHashCode(Object): Returns the same hashcode for the given object as would be returned by the default method hashCode(), whether or not the given object’s class overrides hashCode().
  • load(String): Loads the specified filename as a dynamic library.
  • loadLibrary(String): Loads the system library specified by the libname argument.
  • runFinalization(): Runs the finalization methods of any objects pending finalization.
  • runFinalizersOnExit(boolean): 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.
  • setErr(PrintStream): Reassigns the “standard” error output stream.
  • setIn(InputStream): Reassigns the “standard” input stream.
  • setOut(PrintStream): Reassigns the “standard” output stream.
  • setProperties(Properties): Sets the system properties to the Properties argument.
  • setSecurityManager(SecurityManager): Sets the System security.
Reference Docs :
Oracle System Class

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