Java死锁的例子

桃扇骨 2022-07-14 07:07 175阅读 0赞

1、一个Java死锁的程序

public class DeadLock {
    
    	private String A = "A";
    	private String B = "B";
    
    	public static void main(String[] args) {
    		new DeadLock().deadLock();
    
    	}
    
    	private void deadLock() {
    
    		Thread t1 = new Thread(new Runnable() {
    			@Override
    			public void run() {
    				synchronized (A) {
    					try {
    						Thread.sleep(2000);
    					} catch (InterruptedException e) {
    						e.printStackTrace();
    					}
    					synchronized (B) {
    						System.out.println("Thread t1");
    					}
    
    				}
    
    			}
    		});
    
    		Thread t2 = new Thread(new Runnable() {
    			@Override
    			public void run() {
    				synchronized (B) {
    					try {
    						Thread.sleep(2000);
    					} catch (InterruptedException e) {
    						e.printStackTrace();
    					}
    					synchronized (A) {
    						System.out.println("Thread t2");
    					}
    
    				}
    
    			}
    		});
    
    		t1.start();
    		t2.start();
    	}
    }

2、编译运行Java程序

[root@cent01 javatest]# javac DeadLock.java 
    [root@cent01 javatest]# java DeadLock

3、利用 jps 查看当前的Java程序

[root@cent01 ~]# jps
    2672 Jps
    2661 DeadLock

4、利用 jstack 查看死锁信息

[root@cent01 ~]# jstack 2661
    Found one Java-level deadlock:
    =============================
    "Thread-1":
      waiting to lock monitor 0x092cba78 (object 0xa1847358, a java.lang.String),
      which is held by "Thread-0"
    "Thread-0":
      waiting to lock monitor 0x092cadd0 (object 0xa1847380, a java.lang.String),
      which is held by "Thread-1"
    
    Java stack information for the threads listed above:
    ===================================================
    "Thread-1":
    	at DeadLock$2.run(DeadLock.java:42)
    	- waiting to lock <0xa1847358> (a java.lang.String)
    	- locked <0xa1847380> (a java.lang.String)
    	at java.lang.Thread.run(Thread.java:745)
    "Thread-0":
    	at DeadLock$1.run(DeadLock.java:24)
    	- waiting to lock <0xa1847380> (a java.lang.String)
    	- locked <0xa1847358> (a java.lang.String)
    	at java.lang.Thread.run(Thread.java:745)
    
    Found 1 deadlock.