I think then it would be the best to send the asynchronous exceptions even if they don't work for blocking I/O operations. The need of killing threads from outside is obvious I think. And there will be for sure some scenarios where the killing doesn't work properly, but to avoid these situations should be a task for the programmer of the code. There are always situations where the design of a programming language will not save the programmer of writing stupid code, e.g. while 1: pass

If there is no way of implementing the killing how should one write an multithreaded long running programm that keeps itself clean for several days or months or years. The advantage of threads are the shared informations and forking is often more difficult to use.

How does Java solve these problems?