import java.util.concurrent.locks.ReentrantLock;

public class Task250725 {
    public static void main(String[] args) {
        ReentrantLock lock = new ReentrantLock();
        try {
            lock.lock();
            System.out.println("First lock");
            lock.lock();
            System.out.println("Second lock");
        } finally {
            lock.unlock();
        }
    }
}

import java.util.concurrent.*;

public class Task280725 {
    public static void main(String[] args) throws Exception {
        ExecutorService executor = Executors.newSingleThreadExecutor();
        Future<String> future = executor.submit(() -> {
            Thread.sleep(1000);
            return "Done";
        });
        
        System.out.println(future.get(500, TimeUnit.MILLISECONDS));
        executor.shutdown();
    }
}

public class Task290725 {
    public static void main(String[] args) {
        Object lock1 = new Object();
        Object lock2 = new Object();
        
        new Thread(() -> {
            synchronized(lock1) {
                synchronized(lock2) {
                    System.out.println("Thread 1");
                }
            }
        }).start();
        
        new Thread(() -> {
            synchronized(lock1) {
                synchronized(lock2) {
                    System.out.println("Thread 2");
                }
            }
        }).start();
    }
}

public class Task300725 {
    public static void main(String[] args) {
        Object lock = new Object();
        
        synchronized (lock) {
            try {
                lock.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        
        System.out.println("Done");
    }
}

import java.util.concurrent.*;

public class Task310725 {
    public static void main(String[] args) throws Exception {
        Callable<String> task = () -> "Result";
        FutureTask<String> future = new FutureTask<>(task);
        
        new Thread(future).start();
        System.out.println(future.get());
    }
}

import java.util.concurrent.CountDownLatch;

public class Task010825 {
    public static void main(String[] args) throws InterruptedException {
        CountDownLatch latch = new CountDownLatch(1);
        
        new Thread(() -> {
            latch.countDown();
            latch.countDown();
        }).start();

        latch.await();
        System.out.println("Completed");
    }
}

import java.util.BitSet;

public class Task040825 {
    public static void main(String[] args) {
        BitSet bs1 = new BitSet();
        bs1.set(65);
        
        BitSet bs2 = new BitSet();
        bs2.set(64);
        
        bs1.and(bs2);
        System.out.println(bs1.cardinality());
    }
}