Example 2-1 is the source of an application that simply displays "Hello World" on stdout. The method accepts arguments in the invocation, but does nothing with them.
// // HelloWorld Application // class HelloWorldApp{ public static void main (String args[]) { System.out.println ("Hello World"); } }
Note that, like C, the method, or function, to be initially executed is identified as main. The keyword public lets the method be run by anyone; static makes main refer to the class HelloWorldApp and no other instance of the class; void says that main returns nothing; and args[] declares an array of type String.
The application is compiled by
$ javac HelloWorldApp.java
It is run by
$ java HelloWorldApp arg1 arg2 ...