public class ThreadTester 
{
    public static void main(String args[]) {
	if (args.length > 0) {
	    if (Integer.parseInt(args[0]) < 0)
	    System.err.println(args[0] + "must be >= 0");
		else {
		    MutableInteger sum = new MutableInteger();
                    int upper = Integer.parseInt(args[0]);
                    Thread thrd = new Thread (new Summation(upper, sum));
                    thrd.start();
                    try {
			thrd.join();
			System.out.println("The sum of " + upper + " is " + sum.getValue());
                    }
                    catch( InterruptedException ie) {}
		}
		
		}
	    else
                System.err.println("Usage: Summation <iinteger value>");
}
}