How To Lock A block of code for a Thread in Java

Question

consider the below code.

public class MyThread extends Thread {

    int limit;

    public MyThread(int limit, String name) {
        super();
        this.limit = limit;
        this.setName(name);
    }

    public void run() {
        printValues();
    }

    private synchronized void printValues() {

        for (int i = 1; i < limit; i++) {
            System.out.println(currentThread().getName() + " No = " + i);
        }

    }
}

Requirement: If a thread starts execution of printValues(), suppose it has to print till 10000. Until it completes its job, no other thread should be able to enter this method.

For this I tried Lock interface as well not able to achieve this.

can anyone throw some inputs on this?

You time will be highly appreciated.

Answer 1

Putting synchronized means a thread has to acquire the lock (monitor) for the object instance. If you enforce only one instance of the object it stops concurrent execution.

Alternatively you can have a static lock to do the same thing

private static final Object lock = new Object();

public void printValues() {
    synchronized(lock) {
        //...
    }
}