Game main loop using Thread. How to ?

Hello !
Is anybody know what happened with threads, which was created by MIDLet when MIDLet will be closed ?
More details: i design a specific game engine for MIDP2.0. In many available resources main game loop implemented through separate Thread, but one thing is just missed - how to correctly stop this thread when player want to exit from game ? Mostly all examples just call notifyDestroyed() and do nothing more. But I think what it is wrong program behaviour. So I have questions to advanced MIDP programmers:
1) Do we need correctly stop all Threads before call notifyDestroyed() or can just forget about it ? (I think need to stop all threads ...). Maybe some documentation or usefull link is available about this or related problem ?
Where get documentation about Threads in Java, and how to VM stop thread during garbage collection. As I think exactly GС will destroy MEDLet threads if I don't stop it manually ?

... But I think that all created threads should be
killed in logical right place. For example, if thread
is using for animation and created in Canvas object,
this thread should be killed before killing Canvas
object (for example command "Exit" have been choosen,
firstly we kill thread, secondly we call destroyApp )
If midlet uses user interface, I never called
notifyDestroyed() from my own created thread, because
application usually should be finished when command is
choosen or some key pressed.I completely agree with both notes, and even think what I was wrong in general - when decide to use main loop paradigm in PC way (strictly speaking I just copy paradigm from PC project). You give me an good idea - use custom-purpose threads instead general-purpose "main-loop" thread. I just will look on this thread from other point of view and use it only for call update() for my canvas and provide way to handle time-depended actions (say for animation). No anything more. So all I will need - proper synchronization when perform time-depended action.
So I can stop that thread from destroyApp() when AMS want to destroy my MIDlet, and I can stop that thread from any event-handler in my canvas (in command handler or just key-pressing handler) and then call notifyDestroyed() in order to stop MIDLet manually. So no more calling notifyDestroyed() from any MIDlet-own threads. What you think ?
Just for intresting - citation from JVM Specification:
2.16.9 Virtual Machine Exit
A Java Virtual Machine terminates all its activity and exits when one of two things happens:
* All the threads that are not daemon threads (�2.17) terminate.
In CLDC specification no any changes in this paragraph was made, so we can say what if we does not stop all threads which we create in MIDlet the MIDLet execution will be endless ? It is intresting - implementation JVM in real device start JVM for each MIDLet or start JVM once and start MIDlets in this one-session JVM ? In first-case it is possible to just stop JVM (with all threads) and release any resources (looks little dirty, but why not ?) in second-case all "zombie" threads can live endless (until device switch off) and just decrease performance and eat resources ...
Need more specification ...
Many thanks to RussianDonz for collaboration.

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