hashmap - java Lock using MAP causing a deadlock -

i have written code 3 threads involved:- 1. thread1 -> decrements map created in main thread 2. thread2 -> responsible checking size of map, once 0, exit 3. thread3 -> starts work once size 0, waits till size 0.

thread1 easy implement, thread2 , thread3 using reentrantlock. problem is, thread2 not breaking once size of map reaches 0 , therefore thread3 blocked forever. not sure, problem. appreciated.

    import java.util.hashmap;     import java.util.map;     import java.util.concurrent.locks.lock;     import java.util.concurrent.locks.reentrantlock;      public class mainclass {      static map<string, string> map = new hashmap<string, string>();      public static void main(string[] args) {         // todo auto-generated method stub         map.put("key1", "valu1");         map.put("key2", "valu1");         map.put("key3", "valu1");         map.put("key4", "valu1");         map.put("key5", "valu1");         map.put("key6", "valu1");         lock lock = new reentrantlock();         decrementthread(lock);         thread3(lock);         thread2(lock);     }      static void decrementthread(lock lock) {         system.out.println("starting decrement thread");         new thread(new runnable() {              @override             public void run() {                 try {                     integer = 0;                     while(i<6) {                     thread.sleep(2000);                     string key = "key" + ((++i).tostring());                     system.out.println(key);                     map.remove(key);                     system.out.println("removed" + map.size());                     }                 } catch(exception e) {                     e.printstacktrace();                 }             }         }).start();     }      static void thread3(final lock lock) {         system.out.println("starting thread3");         new thread(new runnable() {             @override             public void run() {                 lock.lock();                 system.out.println("got lock");                 while(true) {                     //system.out.println(map.size());                     if(map.size() == 0) {                         system.out.println("breaking");                         break;                     }                 }                 system.out.println("unlocking");                 lock.unlock();             }         }).start();     }      static void thread2(final lock lock) {         system.out.println("starting mail thread");         new thread(new runnable() {                      @override             public void run() {                 system.out.println("waiting lock");                 lock.lock();                 system.out.println("thread2 locked");                 lock.unlock();              }         }).start();         }      } 

thanks, amar