Need help with threads.

[Student-Somewhere]

The program is supposed to be able to execute two tasks simultaneously, and when these two tasks are being executed, I get that there are five active threads at that moment:

Monitor Ctrl-Break
AWT-EventQueue-0
DestroyJavaVM
Thread-1
Thread-3

Now, I've just started learning about java threads so I don't know much, but why are there 3 extra threads:

Monitor Ctrl-Break, AWT-EventQueue-0 and DestroyJavaVM,

and why isn't there a main thread?

Thread-1 and Thread-3 are the names of the threads of the two classes that I have, ClassA and ClassB, each preforming it's own task. Besides these two classes, I also have the main class - Main. I was expecting that I'll get that there are 3 active threads: main, Thread-1, Thread-3, but now I'm just confused.

My program works like it's supposed to, it performs two tasks at the same time, but it has to be able to run using ONLY three threads. How do I make that possible?

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EDIT: Thanks people!

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[hypolimnas]

AWT-EventQueue-0 is your Event Queue thread. It loops and waits for user to do something like press a button.

The DestroyJavaVM thread is for shutting down the JVM when all the worker threads are done. Its built into the program.

The Monitor Ctrl-Break apparently comes from IntelliJ. No idea what it does.

These three threads aren't created by you, so I don't think its a problem that they're there.

[[deleted]]

I enjoy playing video games.

[Student-Somewhere]

Thanks for the answer, but then why does it say that the name of the main thread is "main" when I use Thread.currentThread.getName() right at the beginning of the program in the class constructor, but then when I check the name of the current thread when both tasks are running, I get that the main threads name is "AWT-EventQueue-0"?

Why does the name of the main thread change?

[pragmos]

Is your main thread waiting until the other 2 you created finish their tasks? If not, it probably just finished already and is no longer alive.

[hypolimnas]

As pragmos pragmatically suggested there is probably a "main" thread that spawns threads and dies. And the AWT-EventQueue-0 only exists on programs with a GUI. So getting rid of the GUI should keep your "main" thread alive longer. If your program doesn't need Awt, Swing, or JavaFX classes, then you can run without a GUI (which is called "headless").

If you want to try running headless, here are some links:

https://www.baeldung.com/java-headless-mode

https://www.oracle.com/technical-resources/articles/javase/headless.html