Purpose of System Class in Java

System class belongs to the package java.lang. It cannot be instantiated.

A System class provides −

• standard output.
• error output streams.
• standard input and access to externally defined properties and environment variables.
• A utility method for quickly copying a portion of an array.
• a means of loading files and libraries.

Following are the fields for java.lang.System class −

• static PrintStream err ? This is the "standard" error output stream.
• static InputStream in ? This is the "standard" input stream.
• static PrintStream out ? This is the "standard" output stream.