Java : "String[] args" arguement in Main Method

public static void main(String [] args)

Those are for command-line arguments in Java.
In other words, if you run

java MyProgram one two

Then args contains:
[ "one", "two" ]

public static void main(String [] args) {
   String one = args[0]; //=="one"
   String two = args[1]; //=="two"
}

The reason for this is to configure your application to run a particular way or provide it with some piece of information it needs.