In intellij 2020.1, when I hit play in debugger, how to stop it from switching threads? (not duplicate)

Question

I perhaps was not clear enough in this question

https://stackoverflow.com/questions/62958507/how-to-have-intellij-play-just-the-thread-i-am-debugging-like-eclipse-does

so it was marked as duplicate of

switching between threads in Intellij Idea

but I did that and changed my breakpoint suspend policy to 'Thread'. This did not change the behavior at all so I am providing code now here.

Here is my code for this test

public class TestDebugger {
    private static final Logger log = LoggerFactory.getLogger(TestDebugger.class);
    private Executor exec = Executors.newFixedThreadPool(5);

    public static void main(String[] args) throws InterruptedException {
        new TestDebugger().start();

        Thread.sleep(10000000);
    }

    private void start() {
        Runnable r = new Runnable() {
            @Override
            public void run() {
                log.info("logger BREAKPOINT A thread="+Thread.currentThread().getName());
                log.info("logger A");

                log.info("logger A");
                log.info("logger A");
                log.info("logger A");
                log.info("logger A");
                log.info("logger A");
                log.info("logger BREAKPOINT B"+Thread.currentThread().getName());

            }
        };

        exec.execute(r);
        exec.execute(r);
        exec.execute(r);
    }
}

I start up the program and threads 1,2,3 all stop on breakpoint A. This part is good. Then I hit the play button while on thread 1 and behind my back, it switches threads!!! This is very annoying and not desired. In fact, I feel the eclipse debugger here works MUCH better as that is the default behavior.

In fact, if I hit play 6 times for all 3 threads, this is the logs...

NOTE: If I remove the other log statements in the middle, it starts working again as I would expect.......weird

INFO: logger BREAKPOINT A thread=pool-2-thread-1
INFO: logger BREAKPOINT A thread=pool-2-thread-3
INFO: logger BREAKPOINT Bpool-2-thread-3
INFO: logger BREAKPOINT Bpool-2-thread-1
INFO: logger BREAKPOINT A thread=pool-2-thread-2
INFO: logger BREAKPOINT Bpool-2-thread-2

The first TWO logs should both be thread 1 but instead it's thread 1, then thread 3....grrrr. Anyway to get this to work?

thanks, Dean

Answer 1

This behavior is by design and there is no way to change it at the moment. Source: developer responsible for IntelliJ IDEA debugger.