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

The main thread is also a user thread which is being created and its lifecylce is similar to any other user thread for that matter.
The other user threads are not dependent on the main thread for any reason unless you set the threads as daemon threads. Once the main thread completes its work it ends(it neither ends the other user threads nor will end the process because the other user threads are running).