以下代码是单线程间通信示例
    但是如果应用在多线程中会存在诸如一下问题

    1. LinkedList数据为空时，执行removeFirst方法
    2. LinkedList元素为10时，执行addLast方法 ```java import org.w3c.dom.events.Event; import sun.management.counter.perf.PerfInstrumentation;

    import java.util.LinkedList; import java.util.concurrent.TimeUnit;

    public class EventQueue { private final int max;

    1. static class Event {
    3. }
    5. private final LinkedList<Event> eventQueue = new LinkedList<>();
    7. private final static int DEFAULT_MAX_EVENT = 10;
    9. public EventQueue() {
    11.     this(DEFAULT_MAX_EVENT);
    12. }
    14. public EventQueue(int max) {
    15.     this.max = max;
    16. }
    18. public void offer(Event event) {
    19.     synchronized (eventQueue) {
    20.         if (eventQueue.size() >= max) {
    21.             console("the queue is full.");
    22.             try {
    23.                 eventQueue.wait();
    24.             } catch (InterruptedException e) {
    25.                 e.printStackTrace();
    26.             }
    27.         }
    29.         console("the new event is submitted");
    31.         eventQueue.addLast(event);
    32.         eventQueue.notify();
    33.     }
    34. }
    36. public Event take() {
    37.     synchronized (eventQueue) {
    38.         if (eventQueue.isEmpty()) {
    39.             console("the queue is empty");
    40.             try {
    41.                 eventQueue.wait();
    42.             } catch (InterruptedException e) {
    43.                 e.printStackTrace();
    44.             }
    45.         }
    46.         Event event = eventQueue.removeFirst();
    47.         this.eventQueue.notify();
    48.         console("the event " + event + "is handle");
    50.         return event;
    52.     }
    53. }
    55. private void console(String message) {
    56.     System.out.printf("%s:%s\n", Thread.currentThread().getName(), message);
    57. }
    59. public static void main(String[] args) {
    60.     final EventQueue eventQueue = new EventQueue();
    61.     new Thread(() -> {
    62.         for (; ; ) {
    63.             eventQueue.offer(new EventQueue.Event());
    64.         }
    65.     }, "Producer").start();
    67.     new Thread(() -> {
    68.         for (; ; ) {
    69.             eventQueue.take();
    70.             try {
    71.                 TimeUnit.SECONDS.sleep(10);
    72.             } catch (InterruptedException e) {
    73.                 e.printStackTrace();
    74.             }
    75.         }
    76.     }, "Consumer").start();
    77. }

    }

    ``` 改进为多线程通信可用
    改进点：

    1. 将if判断改为while
    2. 将notify更改为notifyAll即可