java 死锁 Java 线程死锁的问题解决办法

public class DeadLock {
  public static void main(String[] args) {
    Object obj = new Object();
    Object obj1 = new Object();
    DeadLockThread1 D1 = new DeadLockThread1(obj, obj1);
    DeadLockThread2 D2 = new DeadLockThread2(obj, obj1);
    new Thread(D1,"线程1").start();
    new Thread(D2,"线程2").start();
  }
}

class DeadLockThread1 implements Runnable {
  private Object obj;
  private Object obj1;

  public DeadLockThread1(Object obj, Object obj1) {
    this.obj = obj;
    this.obj1 = obj1;
  }

  @Override
  public void run() {
    synchronized (obj) {   //DeadLockThread1锁定obj对象
      try {
        Thread.sleep(1000);
        synchronized (obj1) { //等待锁定obj1对象，obj对象已被DeadLockThread2锁定
          obj1.getClass();
        }
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
    }
  }
}

class DeadLockThread2 implements Runnable {
  private Object obj;
  private Object obj1;

  public DeadLockThread2(Object obj, Object obj1) {
    this.obj = obj;
    this.obj1 = obj1;
  }

  @Override
  public void run() {
    synchronized (obj1) {   //DeadLockThread2锁定obj2对象
      try {
        Thread.sleep(1000);
        synchronized (obj) { //等待锁定obj对象，obj对象已被DeadLockThread1锁定
          obj.getClass();
        }
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
    }
  }
}