没有获得用于打印具有不同线程的偶数和奇数的desried输出

Question

Hi I am trying to print the even and odd numbers with the help of two different threads but i am not able to get the output .Below is the program .

public class oddeven 
{
    static volatile Integer t= 0;
public static void main(String as[])
{  
    Object ob = new Object ();
    /*oddrunnable or= ;
    evenrunnable er=;*/

    Thread t1 = new Thread (new oddrunnable(t,ob),"odd");
    Thread t2 = new Thread ( new evenrunnable(t,ob),"even");

    t1.start();
    t2.start();




}

}
class oddrunnable implements Runnable
{
    Integer t ;
    Object ob = new Object ();
    public oddrunnable(Integer t,Object ob)
    {
        this.t =  t;
        this.ob= ob;
    }
    @Override
    public void run()
    {
        // TODO Auto-generated method stub

        synchronized (ob) { 
        while (true)
        {if (t%2==0)
            {
                try {
                    ob.wait();
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            try {
                Thread.sleep(300);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            System.out.println("Current thread id "+Thread.currentThread().getName()+"value of integer is "+t);;
            t++;
            ob.notify();
        }
    }
    }

}
class evenrunnable implements Runnable
{
    Integer t ;
    Object ob = new Object ();
    public evenrunnable(Integer t, Object ob)
    {
        this.t =  t;
        this.ob= ob;
    }


    @Override
    public void run()
    {
        synchronized (ob) {
            while (true)
            {
            if (t%2!=0)
                {
                try {
                        ob.wait();
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }try {
                    Thread.sleep(300);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                t++;
                System.out.println("Current thread id "+Thread.currentThread().getName()+"value of integer is "+t);

                ob.notify();
            }
        }
    }

}

i want the output as below :

Current thread id evenvalue of integer is 0
Current thread id oddvalue of integer is 1
Current thread id evenvalue of integer is 2
Current thread id oddvalue of integer is 3
Current thread id evenvalue of integer is 4
Current thread id oddvalue of integer is 5
Current thread id evenvalue of integer is 6
Current thread id oddvalue of integer is 7

but i am getting it wrong as below .

Current thread id evenvalue of integer is 1
Current thread id oddvalue of integer is 0
Current thread id oddvalue of integer is 1
Current thread id evenvalue of integer is 2
Current thread id evenvalue of integer is 3
Current thread id oddvalue of integer is 2
Current thread id oddvalue of integer is 3
Current thread id evenvalue of integer is 4
Current thread id evenvalue of integer is 5
Current thread id oddvalue of integer is 4
Current thread id oddvalue of integer is 5
Current thread id evenvalue of integer is 6
Current thread id evenvalue of integer is 7
Current thread id oddvalue of integer is 6

Also while trying to debug the program gets stuck up . where i am going wrong ?

Answer 1

One thing wrong with your code is that both evenrunnable and oddrunnable increment a different variable. Each has its own t member.

If you want them to increment static volatile Integer t= 0; , remove the Integer t instance variable from those classes.

Passing the static t to the constructor of those classes only passes a copy of its reference. Since Integer is immutable, t++ creates a new Integer and assigns it to the instance variable t , which doesn't affect the static variable t .