[vikky@server ~]$ ls HelloWorld.java 
HelloWorld.java
[vikky@server ~]$ cat HelloWorld.java 
class HelloWorld{
        public static final void main(String []args){
                System.out.println("greencookie is a n00b");
        }
}
[vikky@server ~]$ javac HelloWorld.java 
[vikky@server ~]$ ls HelloWorld.*
HelloWorld.class  HelloWorld.java
[vikky@server ~]$ java HelloWorld
greencookie is a n00b