30 January 2011

Java Threads - Why you can't start a thread twice?

Assume the following code
class Mythread extends Thread {
          }


          Mythead thread = new Mythread(); 
          thread.start(); thread.start();

Why you cannot start the thread (i.e calling thread.start()) twice? Why JVM panics when you do that?

6 comments:

  1. Bala VijayJanuary 30, 2011 at 11:16 PM

    If you want, create a new Thread object and start it. Thread has a lifecycle. Each thread is unique. Why do you want to start a Thread twice? It cant get birth twice. What is your opinion?

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  2. LakshmiJanuary 31, 2011 at 1:16 PM

    @Bala Vijay

    your answer is absolutely rocking :-).

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  3. Sandeep KanabarJanuary 31, 2011 at 11:49 PM

    Say you make a journey from A to B. A journey done is gone. To again go from A to B, you've to start a new journey. Its like Once A human being dies and life ends, he can't re-start his life:-) - the JVM [Yamaraj] marks the Thread[human being] as DEAD. Makes me wonder if our Yamaraj too uses .start() method:-)

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  4. Bala VijayFebruary 3, 2011 at 10:02 PM

    @lakshmi: Thanks Guruji :-)

    ReplyDelete
  5. AnonymousDecember 10, 2011 at 12:52 PM

    in case of creating a thread and killing it and assigning back to another client requires of starting thread twice

    ReplyDelete
  6. AnonymousAugust 19, 2015 at 12:09 PM

    @Sandy, Nice real life example...
    Thanks and carry on...

    ReplyDelete