public class Threads1{  int x = 0;  public class Runner implements Runnable{   public void run(){   int current = 0;    for(int i=0; i < 4; i++) {     current = x;     System.out.print(current + ", ");      x = current + 2;    }   }  }  public static void main(String[ ] args) {   new Thread1().go();  }  public void go() {    Runnable r1 = new Runner();    new Thread(r1).start();    new Thread(r1).start();  } }