public class Racer implements Runnable { int d = 42; public void run () { System.out.println("Thread 2!"); doSomething(1001); //d = 0; // (1) } public static void main (String[] args){ Racer racer = new Racer(); Thread t = new Thread(racer); t.start(); Thread t2 = new Thread(racer); t2.start(); System.out.println("Thread main!"); doSomething(1000); int c = 420 / racer.d; // (2) System.out.println(c); } static void doSomething (int n) { try { Thread.sleep(n); } catch (InterruptedException ix) {} } }