3 Threads Printing numbers in sequence

Question

I am trying to write a simple code to print numbers in sequence. Scenario is like

Thread  Number
T1        1
T2        2
T3        3
T1        4
T2        5
T3          


        

Answer 1

package ThreadCoreConcepts;

import java.util.ArrayList;
import java.util.List;

/**
 * 3 Thread T1,T2,T3 will print output {1,2,3 4,5,6 7,8,9} Where T1 will print
 * {1,4,7} , T2 will print { 2,5,8} and T3 will print {3,6,9}
 * 
 * @author harsmahe
 *
 */
public class ThreeThreadSequenceGen {
    private volatile static int value = 1;

    public static void main(String args[]) throws InterruptedException {
        ThreeThreadSequenceGen gen = new ThreeThreadSequenceGen();
        Object mutex = new Object();
        Thread t1 = new Thread(gen.new RunThread(1, mutex));
        t1.setName("1");
        Thread t2 = new Thread(gen.new RunThread(2, mutex));
        t2.setName("2");
        Thread t3 = new Thread(gen.new RunThread(3, mutex));
        t3.setName("3");
        t1.start();
        t2.start();
        t3.start();

    }

    class RunThread implements Runnable {
        private int start = 0;
        private Object mutex;
        private List list = new ArrayList();

        public RunThread(final int start, Object mutex) {
            // TODO Auto-generated constructor stub
            this.start = start;
            this.mutex = mutex;
        }

        @Override
        public void run() {
            try {
                while (value <= 9) {
                    // while (true) {
                    // TODO Auto-generated method stub
                    int name = Integer.valueOf(Thread.currentThread().getName());
                    // System.out.println("[" + Thread.currentThread().getName()
                    // + "]");
                    // notifyAll();

                    synchronized (mutex) {
                        if (name == 1 && value == start) {
                            list.add(value);
                            System.out.println("[" + Thread.currentThread().getName() + "]" + value);
                            start = start + 3;
                            value++;
                            mutex.notifyAll();
                            mutex.wait();
                        } else if (name == 2 && value == start) {
                            System.out.println("[" + Thread.currentThread().getName() + "]" + value);
                            list.add(value);
                            start = start + 3;
                            value++;
                            mutex.notifyAll();
                            mutex.wait();

                        } else if (name == 3 && value == start) {
                            System.out.println("[" + Thread.currentThread().getName() + "]" + value);
                            list.add(value);
                            start = start + 3;
                            value++;
                            mutex.notifyAll();
                            if (value < 9) {
                                mutex.wait();
                            }

                        } else {
                            mutex.notifyAll();
                            // mutex.wait();
                        }
                    }

                }

            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                // System.out.println(list);
            }

        }

    }
}

    enter code here