Question

Basically what it does is that it prints the following numbers multiple of 2 and 3 in sequence like this

 2       3       4       6       6       9       8       12      10    = this is the output
(2*1=2) (3*1=3) (2*2=4) (3*2=6) (2*3=6) (3*3=9) (2*4=8) (3*4=12) (2*5=10) = just a guide

here’s my code so far, I’m having trouble displaying it in sequence. I’ve tried using wait and notify but it’s a mess. So far this one is working.

public class Main {

    public static void main(String[] args) throws InterruptedException {

        final Thread mulof2 = new Thread(){
            public void run() {
                for (int i = 1; i <= 10; i++) {
                    int n = 2;
                    int result = n * i;
                    System.out.print(result + " ");
                }
            }
        };
        Thread mulof3 = new Thread(){
            public void run() {
                for (int i = 1; i <= 10; i++) {
                    int n = 3;
                    int result = n * i;
                    System.out.print(result + " ");
                }
            }
        };
        mulof2.start();
        mulof3.start();

    }

}

Answer 1

With Java 7 your first choice should be a Phaser. You’ll only need one instance of it, created with new Phaser(1). You’ll need just two methods for coordination: arrive and awaitAdvance.