running 3 threads in sequence java

Question

I have 3 threads 1st printing A 2nd printing B 3rd printing C

I want to print in sequence A B C A B C A B C and so on.....

So I wrote the program below, but

Answer 1

I was asked to write a similar program in an interview with the added condition that it should be extensible in a way that we can provide our own count of threads and they should print characters with the first thread printing 'A' and then the subsequent threads printing B, C, D and so on. Here's how I did it.

public class AlternateCharPrinter {

    public static char ch = 65;

    private static void createAndStartThreads(int count) {
        Object lock = new Object();
        for (int i = 0; i < count; i++) {
            new Thread(new AlternateCharRunner((char) (65 + i), lock)).start();
        }

    }

    public static void main(String[] args) {
        createAndStartThreads(4);
    }

}

class AlternateCharRunner implements Runnable {

    private char ch;
    private Object lock;
    private static int runnerCount;

    public AlternateCharRunner(char ch, Object lock) {
        this.ch = ch;
        this.lock = lock;
        runnerCount++;
    }

    @Override
    public void run() {
        while (true) {
            synchronized (lock) {
                while (ch != AlternateCharPrinter.ch) {
                    try {
                        lock.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                System.out.println(AlternateCharPrinter.ch++);
                if (AlternateCharPrinter.ch == (65 + runnerCount)) {
                    AlternateCharPrinter.ch = 65;
                }
                lock.notifyAll();
            }
        }
    }

}