死锁

死锁

• 

• 死锁测试，怎么排除死锁：

  public class Test01 {
      public static void main(String[] args) {
          String lockA = "lockA";
          String lockB = "lockB";
          new Thread(new MyThread(lockA, lockB), "T1").start();
          new Thread(new MyThread(lockB, lockA), "T2").start();
      }
  }
  
  class MyThread implements Runnable {
      private String lockA;
      private String lockB;
  
      public MyThread(String lockA, String lockB) {
          this.lockA = lockA;
          this.lockB = lockB;
      }
  
      @Override
      public void run() {
          synchronized (lockA) {
              System.out.println(Thread.currentThread().getName() + "lock:" + lockA + "=>get" + lockB);
              try {
                  TimeUnit.SECONDS.sleep(2);
              } catch (InterruptedException e) {
                  e.printStackTrace();
              }
              synchronized (lockB) {
                  System.out.println(Thread.currentThread().getName() + "lock:" + lockB + "=>get" + lockA);
              }
          }
      }
  }
  

  • 解决问题

    1、使用 jps -l 定位进程号
    cmd 窗口 输入 jps -l

    

    2、使用 jstack 进程号 找到死锁问题