java deadlock while printing sequence using two threads

truekiller :

I tried to print Odd and Even Numbers Alternatively using two thread. But the program entered a deadlock. I am not able to understand why it is entering a deadlock. In debug mode, program behaves differently. It prints 1 2 then deadlock. This behavior is unexpected.

Expected Output

1
2
3
4
odd thread ends here    
even thread ends here    
main thread ends here

Current Output

1
2
3
4
odd thread ends here
(Deadlock)

Here is the java code

public class PrintSequence {    
    public static void main(String[] args) {
        EvenOddPrinter printer = new EvenOddPrinter(false, 1, 4);
        Thread odd = new Thread(new Runnable() {    
            @Override
            public void run() {
                printer.printOdd();    
            }
        });
        Thread even = new Thread(new Runnable() {
            @Override
            public void run() {
                printer.printEven();
            }
        });
        odd.start();
        even.start();
        try {
            odd.join();
            System.out.println("odd thread ends here");
            even.join();
            System.out.println("even thread ends here");
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("main thread ends here");
    }

}

class EvenOddPrinter {

    private boolean isEven;
    private int index;
    private int maxNumber;

    public EvenOddPrinter(boolean isEven, int index, int maxNumber) {
        super();
        this.isEven = isEven;
        this.index = index;
        this.maxNumber = maxNumber;
    }

    public synchronized void printOdd () {
        while(index < maxNumber) {
            if(!isEven) {
                System.out.println(index);
                index++;
                isEven = true;
                notify();
            }
            try {
                wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }   
    public synchronized void printEven() {
        while(index <= maxNumber) {
            if(isEven) {
                System.out.println(index);
                index++;
                isEven = false;
                notify();
            }
            try {
                wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

Can someone help me in fixing this?

WJS :

When odd finishes, it never notifies the even thread. So do this.

    public synchronized void printOdd () {
        while(index < maxNumber) {
            if(!isEven) {
                System.out.println(index);
                index++;
                isEven = true;
                notify();
            }
            try {
                wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        notify(); // add a notify here
    }