Why is this program which loops many times taking time when there is a `println` after the loops?

Here is the small code which I am trying. This program takes good amount of time to execute. While running, if I try to kill it through the terminate button in eclipse, it returns Terminate Failed. I can kill it from terminal using kill -9 <PID>.

But, when I don't print the variable result in the last line of the program (Please check the commented portion of the code), the program exits immediately.

I am wondering :

1. Why is it taking time to execute when the value of result is being printed?
   Please note, if I don't print value, the same loop gets over immediately.

2. Why is eclipse not able to kill the program?

Update 1 : It seems JVM is optimize the code during the runtime (not in compile time). This thread is helpful.

Update 2 : When I print the value of value, jstack <PID> is not working. Only jstack -F <PID> is working. Any possible reason?

    public class TestClient {

        private static void loop() {
            long value =0;

            for (int j = 0; j < 50000; j++) {
                for (int i = 0; i < 100000000; i++) {
                    value += 1;
                }
            }
            //When the value is being printed, the program 
            //is taking time to complete
            System.out.println("Done "+ value);

            //When the value is NOT being printed, the program 
            //completes immediately
            //System.out.println("Done ");
        }

        public static void main(String[] args) {
            loop();
        }
    }