Java Multithreading (ii) Change of Synchronized lock object

 Public classMyService {PrivateString lock = "123";  Public voidTestMethod () {synchronized(lock) {System.out.println (Threadb.currentthread (). GetName ()+ "Begin" +System.currenttimemillis ()); Lock= "456"; Try{threadb.sleep (2000); System.out.println (Threadb.currentthread (). GetName ()+ "End" +System.currenttimemillis ()); } Catch(interruptedexception e) {//TODO auto-generated Catch blockE.printstacktrace (); }        }    }    }

Lock lock changed from "123" to "456"

Threada and THREADB

 Public classThreadaextendsThread {PrivateMyService MyService;  PublicThreada (MyService myservice) { This. MyService =MyService; }     Public voidrun () {Myservice.testmethod (); }} Public classThreadbextendsThread {PrivateMyService MyService;  Publicthreadb (MyService myservice) { This. MyService =MyService; }     Public voidrun () {Myservice.testmethod (); }}

View Code

Run

 Public class Run {    publicstaticvoidthrows  interruptedexception {         New  myservice ();                Threada Threadanew  Threada (myservice);        Threada.start ();        Thread.Sleep (+);        Threada threadbnew  Threada (myservice);        Threadb.start ();            }        }

If Thread.Sleep (50) is commented out, the locks acquired by A and B are "123", although the lock is changed to "456", the result is still synchronous.

Java Multithreading (ii) Change of Synchronized lock object