public class ClientThread extends Thread {

    private final RequestQueue queue;

    private final Random random;

    private final String sendValue;

    public ClientThread(RequestQueue queue, String sendValue) {
        this.queue = queue;
        this.sendValue = sendValue;
        this.random = new Random(System.currentTimeMillis());
    }

    @Override
    public void run() {

        for (int i = 0; i < 10; i++) {
            System.out.println("Client -> request " + sendValue);
            queue.putRequest(new Request(sendValue));

            try {
                Thread.sleep(random.nextInt(1000));
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

public class Request {

    private final String value;

    public Request(String value) {
        this.value = value;
    }

    public String getValue() {
        return value;
    }
}

public class RequestQueue {

    private final LinkedList<Request> queue = new LinkedList<>();

    public Request getRequest() {
        synchronized (queue) {
            while (queue.size() <= 0) {
                try {
                    queue.wait();
                } catch (InterruptedException e) {
                    return null;
                }
            }
            return queue.removeFirst();
        }
    }

    public void putRequest(Request request) {

        synchronized (queue) {
            queue.addLast(request);
            queue.notifyAll();
        }
    }
}

public class ServerThread extends Thread {

    private final RequestQueue queue;

    private final Random random;

    private volatile boolean closed = false;

    public ServerThread(RequestQueue queue) {
        this.queue = queue;
        random = new Random(System.currentTimeMillis());
    }

    @Override
    public void run() {

        while (!closed) {
            Request request = queue.getRequest();
            if (null == request) {
                System.out.println("Received the empty request.");
                continue;
            }
            System.out.println("Server ->" + request.getValue());
            try {
                Thread.sleep(random.nextInt(1000));
            } catch (InterruptedException e) {
                return;
            }
        }
    }

    public void close() {
        this.closed = true;
        this.interrupt();
    }
}

public class SuspensionClient {
    public static void main(String[] args) throws InterruptedException {

        final RequestQueue queue = new RequestQueue();
        new ClientThread(queue,"Jack").start();
        ServerThread serverThread =  new ServerThread(queue);
        serverThread.start();

        Thread.sleep(10000);
        serverThread.close();
    }
}