Warranty of storing variable value before next command in java -

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i curious if after value assign command this:

a = 5;

there warranty new value has been stored variable? , if different primitive , other data types? , runnable objects.

i have run method in myclass containing:

synchronized(this){      while(pleasewait){          try { system.out.println("sleeping"); wait();}          catch (exception e) {        e.printstacktrace(); }      }   }

is other classes calling method sleepme() contains:

synchronized (myclass){             myclass.pleasewait = true;             myclass.notify(); }

and question is, have insert waiting after calling sleepme, instance of myclass have time change value of myclass.pleasewait ?

i have several set methods, assing complex objects (objects of objects) instance of myclass.

thanks

the fact 2 threads synchronizing on same object means changes made pleasewait 1 thread visible other thread when returns wait() call. synchronization (in case regaining of lock on this when return wait() call) provides required "happens before" relationship between 2 threads ensure update visible.

so answer question:

  • any solution requires 1 thread "wait" in sense. that's inherent in problem.

  • what doing sufficient. don't need add additional waiting. wait/notify mechanism ensures thread wait() see up-to-date copy of variable ... provided changes made while holding object lock.

  • you can implement kind of thing using higher level concurrency classes.

  • you implement using volatile , "busy waiting" ... bad idea.


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