JVM Thread DUmp文件分析-定位死锁

小灰灰 2023-01-08 12:23 130阅读 0赞

源代码如下：

package com.mytest.Learning;
    
    public class DeadLock { 
        public static void main(String [] args){ 
            final Object resource1 = "resource1";
            final Object resource2 = "resource2";
    
            Thread t1 = new Thread(() -> { 
                synchronized (resource1){ 
                    System.out.println("thread1 lock resource1");
    
                    try { 
                        Thread.sleep(30);
                    } catch (InterruptedException e) { 
                        e.printStackTrace();
                    }
    
                    synchronized (resource2){ 
                        System.out.println("thread1 locked resource2");
                    }
                }
            });
    
            Thread t2 = new Thread(() -> { 
                synchronized (resource2){ 
                    System.out.println("Thread2 locked resource2");
    
                    try { 
                        Thread.sleep(30);
                    } catch (InterruptedException e) { 
                        e.printStackTrace();
                    }
    
                    synchronized (resource1){ 
                        System.out.println("Thread2 locked resource1");
                    }
                }
            });
    
            t1.start();
            t2.start();
            try { 
                t1.join();
                t2.join();
            } catch (InterruptedException e) { 
                e.printStackTrace();
            }
            System.out.println("DeadLock released");
        }
    }

启动运行结果如下：

thread1 lock resource1
    Thread2 locked resource2

定位如下：  
jps查看死锁程序进程id  
jps命令  
![在这里插入图片描述][2021012010072154.jpg]  
jstack获取ThreadDump，建议dump至少3次，每次间隔10-20s，这样的dump结果比较准确  
![在这里插入图片描述][20210120100731999.jpg]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2EyMDA4MjIxNDYwODU_size_16_color_FFFFFF_t_70]

[2021012010072154.jpg]: /images/20221119/806414c02fbf4401b19c105ee123d6cf.png
[20210120100731999.jpg]: /images/20221119/dec65722424f4d98811b3e3ee385285d.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2EyMDA4MjIxNDYwODU_size_16_color_FFFFFF_t_70]: /images/20221119/db9bbfbf02eb49b4af85c6ddfbb0f6f8.png