//Simple java program print "HELLO WORLD!" on console.

CODE
public class Hello {
            public static void main(String[] args){
                      System.out.println("HELLO WORLD!");
            }
}

EXECUTION
Copy the above code paste it in notepad and save with name "Hello.java" without quotes.
I am saving in my D:\java_programs\ folder

Now open the command prompt
Type the following code
C:\Users\Administrator>D:
D:\>cd java_programs
D:\java_programs>javac Hello.java
D:\java_programs>java Hello
if it show error like "Error: Could not find or load main class type
D:\java_programs>java -classpath . Hello.java
HELLO WORLD!
D:\java_programs>

OUTPUT