public class MyApplication{

    public static void main(String[] arguments){
        System.out.println("Hello World!");
    }
}

javac MyApplication.java  //this will compile it
java MyApplication  //this will run the main method of MyApplication

java MyApplication some_file.txt // Run application with one arg.

public class MyApplication{

    public static void main(String[] arguments){
        System.out.println("Hello World!");
        System.out.println("You entered: " + arguments[0]);
    }
}