Why does a thread outlive the main method in Java?

Question

I was teaching myself Java threading and I noticed something that confuses me a little. I made a class called engine implementing Runnable. The r

Answer 1

If you want your program to exit when the main method finished, consider making your threads daemons. But take care of the fact, that daemon threads will be aborted, when main finishes.
You can create a daemon thead like so:

Thread t = new Thread(...);
t.setDaemon(true);

All non-daemon threads are user threads. Those threads are stopping the jvm from closing.