Deadlock troubleshooting Tips-using the JDK's own management tools Jstack

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Development time is long, will inevitably write some of the code of the deadlock, oneself clearly call this method can be not executed, not into the method, the log does not print!

Here we simulate a deadlock code, using the JDK's own management tool to troubleshoot is not a deadlock!

1 //Thinking about code2  Public classDeadlockdemoImplementsrunnable{3 4          Public intFlag = 1;5         //static objects are shared by all objects of the class6         Private StaticObject O1 =NewObject (), O2 =NewObject ();7 @Override8          Public voidrun () {9System.out.println ("flag=" +flag);Ten             if(Flag = = 1) { One                 synchronized(O1) { A                     Try { -Thread.Sleep (500); -  the}Catch(Exception e) { - e.printstacktrace (); -                     } -                     synchronized(O2) { +System.out.println ("1"); -                     } +                 } A             } at             if(flag = = 0) { -                 synchronized(O2) { -                     Try { -Thread.Sleep (500); -}Catch(Exception e) { - e.printstacktrace (); in                     } -                     synchronized(O1) { toSystem.out.println ("0"); +                     } -                 } the             } *         } $ Panax Notoginseng          Public Static voidMain (string[] args) { -  theDeadlockdemo TD1 =NewDeadlockdemo (); +Deadlockdemo TD2 =NewDeadlockdemo (); ATd1.flag = 1; theTd2.flag = 0; +             //The TD1,TD2 is in an executable state, but it is not certain which thread the JVM thread is scheduled to execute first.  -             //TD2 Run () may be running before TD1 run () $             NewThread (TD1). Start (); $             NewThread (TD2). Start (); -  -         } the}

Start the code, after execution has been stuck

Next we use the command JPS in the terminal to query the port number of this class is 7824

Then use the Jstack port number

7824

You can find the deadlock in this section of the program!

Deadlock troubleshooting Tips-using the JDK's own management tools Jstack