Small demo of Condition and ReentrantLock usage

Main.java

package ru.yandex.lc.proto.condition;

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
import java.util.logging.Logger;

public class Main {

    private static Logger log = Logger.getLogger("main");

    private static ReentrantLock lock = new ReentrantLock();

    private static Condition condition = lock.newCondition();

    public static void main(String[] args) throws Exception {
        ExecutorService exe = Executors.newFixedThreadPool(1);
        exe.submit(() -> {
            try {
                Thread.sleep(2000);
                log.info("acquiring lock");
                lock.lock();
                log.info("lock acquired");
                try {
                    log.info("unlocking main thread");
                    condition.signal();
                    Thread.sleep(2000);
                } finally {
                    log.info("Releasing lock");
                    lock.unlock();
                }
            } catch (InterruptedException e) {
                log.severe(e.toString());
            }
        });
        lock.lock();
        try {
            condition.await();
        } finally {
            lock.unlock();
        }
        log.info("main thread unlocked");
        exe.shutdownNow();
    }
}

output.log

12:41:39 AM ru.yandex.lc.proto.condition.Main lambda$main$0
INFO: acquiring lock
12:41:39 AM ru.yandex.lc.proto.condition.Main lambda$main$0
INFO: lock acquired
12:41:39 AM ru.yandex.lc.proto.condition.Main lambda$main$0
INFO: unlocking main thread
12:41:41 AM ru.yandex.lc.proto.condition.Main lambda$main$0
INFO: Releasing lock
12:41:41 AM ru.yandex.lc.proto.condition.Main main
INFO: main thread unlocked