Leader.java

import com.hazelcast.core.Hazelcast;
import com.hazelcast.core.HazelcastInstance;
import com.hazelcast.core.ICountDownLatch;

public class Leader {

    public static void main(String[] args) throws Exception {
        HazelcastInstance hz = Hazelcast.newHazelcastInstance();
        ICountDownLatch latch = hz.getCountDownLatch("countDownLatch");

        System.out.println("Starting");
        // we init the latch with 1, since we only need to complete a single step.
        latch.trySetCount(1);

        // do some sleeping to simulate doing something
        Thread.sleep(30000);

        // now we do a countdown which notifies all followers
        latch.countDown();
        System.out.println("Leader finished");

        // we need to clean up the latch
        latch.destroy();
    }
}