import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

class MyTask implements Runnable {
    private final int MAX_COUNT = 10000;
    private final Lock lock = new ReentrantLock();
    private int sharedCounter = 0;


    public void run() {
        for (int i = 0; i < MAX_COUNT; i++) {
          lock.lock();
          try {
              sharedCounter = sharedCounter + 1;
          } finally {
              lock.unlock();
          }
        }
        System.out.println("Done! Shared counter = " + sharedCounter);
    }
}