Threads and garbage collection

[Micah Wedemeyer]

If I create a Thread and do not maintain a reference to it like:
(new Thread()).start();
then what happens when that Thread's start() method returns? Will it get marked for garbage collection?
Thanks,
Micah

[Thomas Smets]

First of all the code is incorrect

If I create a Thread and do not maintain a reference to it like:
(new Thread()).start();

 
(new Thread ( 
      new Runable()
      {
         public void run ()
         {
             .... // Do your stuff here
         }
      }
            )
         ).start();

Then no the Thread you instanciate is not ready for GC as soon as you quit the line invoking the start () but when the run method of the Runnable. The Thread instance & all the object it may refere may be marked for GC if they are not referenced by anything anymore...
Thomas,

[Micah Wedemeyer]

I knew that Thread would do nothing, it was just an example. My actual object in my application is simply a subclass of Thread.

[Jim Yingst]

Basically, objects may be garbage collected if and only if they are not reachable from any living threads. This means that threads are the starting points for defining what is reachable, and what isn't - and even if no other threads hold any references to a Thread object, once start() has been called it cannot be garbage collected until its run() method completes (whether it completes normally or abruptly).