if (args.length <= 1)

You should check for the number of command line arguments *before*
attempting to access the command line arguments array. This is important
since, if *no* arguments are passed, the array will have zero elements:
hence, any element-access attempt will fail.

Therefore, you might do something along these lines:

   ...
   public static void main(String[] args)
   {
        if (args.length != 2)
        {
             // Don't have two arguments, so assume defaults, or
             // issue error mesage, whatever ...
        }
        else
        {
            // Got two arguments, do other checking, array access,
            // whatever ...
        }
        ...
   }
   ...

I hope this helps.

Anthony Borla