java - notifyAll の呼び出し中に IllegalMonitorStateException が発生しました

Question

notifyAll の呼び出し中に IllegalMonitorException が発生するコードがあります。enQueue() 中、スレッドはデータを追加し、 illegalMonitorException をスローします。

BlockingQueue.class :

public class BlockingQueue {
private Queue<Integer> queue = new LinkedList<>();
private int maxCount;
private Lock lock = new ReentrantLock();

BlockingQueue(int maxCount){
    this.maxCount=maxCount;
}

public  void enQueue(int d) throws InterruptedException {
    lock.lock();
    if(queue.size() >= maxCount){
        System.out.println("going to wait enqueu "+Thread.currentThread().getName() +" size "+queue.size());
        lock.wait();
    }
    System.out.println(" Adding "+d);
    queue.add(d);
    lock.notify();
    lock.unlock();
}

public  Integer deQueue() throws InterruptedException {
    lock.lock();
    if(queue.size()==0){
        System.out.println("going to wait dequeue "+Thread.currentThread().getName()+" size "+queue.size());
        lock.wait();
    }
    int data = queue.remove();
    lock.notify();
    lock.unlock();
    return data;
}}

Main.Class :

 public class Main {
public static void main(String args[]){
    BlockingQueue queue=new BlockingQueue(10);
    Producer p = new Producer(queue);
    Consumer c = new Consumer(queue);

    Thread t1=new Thread(c,"Consumer");
    Thread t2=new Thread(p, "producer");

    t1.start();
    t2.start();
}}

Producer.class :

 public class Producer implements Runnable {
private BlockingQueue q;
Producer(BlockingQueue qu){
    this.q=qu;
}

public Integer generateWork() throws InterruptedException {
    return new Random().nextInt(100 );
}

@Override
public void run() {
    for(int i =0; i<100; i++){
        try {
            Thread.sleep(100);
            q.enQueue(generateWork());
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}}

Consumer.class :

public class Consumer implements Runnable {

private BlockingQueue queue;
Consumer(BlockingQueue q){
    this.queue=q;
}

public void consume(int data){
    System.out.println(" consume "+data);
}

@Override
public void run() {
    for(int i=0; i < 100; i++){
        try {
            Thread.sleep(1000);
            consume(queue.deQueue());
        } catch (InterruptedException e) {
           System.out.println("interrupted");
        }
    }
}}

出力:

追加 94

スレッド「プロデューサー」での例外 java.lang.IllegalMonitorStateException

at java.lang.Object.notify(Native Method)
at BlockingQueue.enQueue(BlockingQueue.java:23)
at Producer.run(Producer.java:20)
at java.lang.Thread.run(Thread.java:748)