Java Multithreading - How to print numbers in natural order

Question

I got it interview that:

Thread-A Prints Even numbers from 0
Thread-B prints Odd numbers from 1

I want to print 0 1 2 3 4.... in natural order till 1000 How can I achive.

I tried this way:

public class ThreadDemo2 {
    static int aa = 0;

    public static void main(String[] args) {
        boolean mytime = true;
        EvenThread et = new EvenThread(mytime);
        OddThread ot = new OddThread(mytime);
        et.start();
        ot.start();

    }

}

class EvenThread extends Thread {
    boolean mytime;
    int i = 0;

    public EvenThread(boolean mytime) {
        this.mytime = mytime;
    }

    public void run() {
        //if (ThreadDemo2.aa == 0) {
            for (int i = 0; i < 1000 && ThreadDemo2.aa == 0; i += 2) {
                System.out.println(i);
                ThreadDemo2.aa = 1;
                try {
                    sleep(500);

                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
        //  }

        }/* else
            try {
                this.wait();
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }*/
    }

}

class OddThread extends Thread {
    boolean mytime;
    int i = 1;

    public OddThread(boolean mytime) {
        this.mytime = mytime;
    }

    public void run() {
        //if (ThreadDemo2.aa == 1) {
            for (int i = 1; i < 1000 && ThreadDemo2.aa == 1; i += 2) {
                System.out.println(i);
                ThreadDemo2.aa = 0;
                try {
                    sleep(500);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            //ThreadDemo2.aa = 0;
        //}
    }

}

Answer 1

Unfortunately you can't expect the result because of JVM working on 2 different threads , but you can do something like that,

public class Test12 {

public static void main(String[] args) {
    Thread1 t1=new Thread1();
    Thread2 t2=new Thread2();


}

}

class Thread1 implements Runnable {

public Thread1() {
    Thread t = new Thread();
    t.start();
}

@Override
public void run() {
    try {
        for (int i = 0; i < 1000; i++) {
            if (i % 2 == 0) {
                System.out.println(i);
            }

        }

    } catch (Exception e) {

    }
}
}

class Thread2 implements Runnable {

public Thread2() {
    Thread t = new Thread(this);
    t.start();

}

@Override
public void run() {
    try {
        for (int i = 0; i < 1000; i++) {
            if (i % 2 == 1) {
                System.out.println(i);
            }

        }

    } catch (Exception e) {

    }
}

}

when you run this application many times, you will notice that there are no result like other 100%