/*
*
*
* lake@localhost:~/java$ javac -version
* javac 1.8.0_65
* lake@localhost:~/java$ java -version
* openjdk version "1.8.0_65"
* OpenJDK Runtime Environment (build 1.8.0_65-b17)
* OpenJDK 64-Bit Server VM (build 25.65-b01, mixed mode)
* lake@localhost:~/java$ uname -a
* Linux localhost.localdomain 4.13.0+ #5 SMP Mon Apr 23 04:09:02 EDT 2018 x86_64 x86_64 x86_64 GNU/Linux
*
* lake@localhost:~/java$ vim HelloWorld.java
* lake@localhost:~/java$ javac HelloWorld.java
* lake@localhost:~/java$ java  HelloWorld
* Hello World.
* lake@localhost:~/java$ ls
* HelloWorld.class  HelloWorld.java
*
* */

public class HelloWorld{
    public static void main(String args[]){
        System.out.println("Hello World.");
    }
}