Semaphore not working as expected ,it is getting locked - multithreading

Question

i am using semaphore for thread communication i have two threads one is OddThread and another is EvenThread ,i am printing value from 1 to 10 OddThread will print only odd numbers between 1 to 10 and EvenThread thread is printing only even numbers between 1 to 10. for that i have used semaphore for threads to communicate properly .what is actually happening is that OddThread is printing only 1 and EvenThread only 2 and then both get stopped. I am not under standing what is actually happening.can any body suggest.
public class ThreadProducerConsumerSemaphore {
/**
* #param args
*/
public static void main(String[] args) {
Semaphore p = new Semaphore(1);
Semaphore c = new Semaphore(0);
OddThread producer = new OddThread(p, c);
EvenThread consumer = new EvenThread(p, c);
Thread t1 = new Thread(producer, "Thread producer");
Thread t2 = new Thread(consumer, "Thread consumer");
t1.start();
t2.start();
}
}
class OddThread implements Runnable {
Semaphore p;
Semaphore c;
public OddThread(Semaphore p, Semaphore c) {
super();
this.p = p;
this.c = c;
}
int counter = 1;
#Override
public void run() {
while (true) {
try {
p.acquire(1);
System.out.println(Thread.currentThread().getName() + " "
+ counter);
if (counter == 10) {
break;
}
counter++;
c.release(1);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
class EvenThread implements Runnable {
Semaphore p;
Semaphore c;
int counter = 2;
public EvenThread(Semaphore p, Semaphore c) {
super();
this.p = p;
this.c = c;
}
#Override
public void run() {
while (true) {
try {
c.acquire(1);
System.out.println(Thread.currentThread().getName() + " "
+ counter);
if (counter == 10) {
break;
}
counter=counter+2;
p.acquire(1);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}

Answer 1

Your code can't be correct, it's not even symmetrical.
p.acquire(1);
c.release(1);
c.acquire(1);
p.acquire(1);

Answer 2

Your EvenThread.run method acquires both c and p, rather than releasing one of them.
Note, however, that your code doesn't look like it'll exit properly even once it's been fixed. Consider: neither thread releases a semaphore before it exits, so one of the threads will inevitably be blocked.

Answer 3

here is your problem:
............
c.acquire(1);
System.out.println(Thread.currentThread().getName() + " "
+ counter);
if (counter == 10) {
break;
}
counter=counter+2;
p.acquire(1); <--deadlock this has already been acquired by the other thread.
..............
you should release p here, to allow the other thread to continue; so replace the line I indicated with p.release(1) and it should be fine.