Producer and Consumer problem in Java

Solving a Producer and Consumer problem  in a multithreading environment following illustration is sited, I have tried to solve the problem using a Queue,  Producer producing the counter and Consumer consumes the counter :


import java.util.LinkedList;
import java.util.Queue;

/**
 * @author sachin.srivastava
 * tek9g.blogspot.com
 *
 */
public class ProducerConsumer extends Thread{

static Queue<Integer> queue = new LinkedList<>();
private static final int capacity = 10;
private static  int counter = 1;
public static void main(String[] args) {
///starting the producer and consumer
new Producer().start();
new Consumer().start();
}

static class Producer extends Thread {
public void run(){
for ( ;;) {
try {
Thread.sleep(2000);
synchronized (queue) {
if( queue.size() <= capacity){
queue.add(counter);
System.out.println("queue added counter produced=" + counter);
counter++;
} else if(queue.size() > capacity)  {
queue.remove(queue.size()-1);
System.out.println("queue is full so can't produce new element");
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
static class Consumer extends Thread {
public void run(){
for (;;) {
try {
Thread.sleep(2000);
synchronized (queue) {
if(!queue.isEmpty()){
Integer head = queue.remove();
System.out.println("queue pop counter consumer=" + head);
} else {
System.out.println("queue is empty so nothing to pop for consumers");
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}

Output : 

queue added counter produced=1

queue pop counter consumer=1

queue added counter produced=2

queue pop counter consumer=2

queue added counter produced=3

queue pop counter consumer=3

queue added counter produced=4

queue pop counter consumer=4

queue added counter produced=5

queue pop counter consumer=5

queue added counter produced=6

queue pop counter consumer=6

queue added counter produced=7

queue pop counter consumer=7

queue added counter produced=8

queue pop counter consumer=8

queue added counter produced=9

queue pop counter consumer=9

queue added counter produced=10

queue pop counter consumer=10

queue added counter produced=11

queue pop counter consumer=11

queue added counter produced=12

queue pop counter consumer=12

queue added counter produced=13

queue pop counter consumer=13

queue added counter produced=14

queue pop counter consumer=14

queue added counter produced=15

queue pop counter consumer=15

queue added counter produced=16

queue pop counter consumer=16

queue added counter produced=17

queue pop counter consumer=17

queue added counter produced=18

queue pop counter consumer=18

queue added counter produced=19

queue pop counter consumer=19

queue added counter produced=20

queue pop counter consumer=20

queue added counter produced=21

queue pop counter consumer=21

queue added counter produced=22

queue pop counter consumer=22

queue added counter produced=23

queue pop counter consumer=23

queue added counter produced=24

queue pop counter consumer=24

queue added counter produced=25

queue pop counter consumer=25

queue added counter produced=26

queue pop counter consumer=26

queue added counter produced=27

queue pop counter consumer=27

queue added counter produced=28

queue pop counter consumer=28

queue added counter produced=29

queue pop counter consumer=29

--------

If you seen the output  starts with the producer 1  then consumer 1  then  producer 2 then consumer 2 and so on ... so the queue always  remain  in the consistent state and also remain thread safe.

Enjoy the coding  !!!!