How to debug a Java Process started by ProcessBuilder

Question

There are two Java files. One is A, and the other is B. Both A and B have main functions. Then I run A, and in A, I start a Process of B through ProcessBuilder.start().

I can debug the code of A. However, I cannot debug B. Even when I add breakpoint in B's main function, Eclipse does not stop at that line of B. So far the only method that I can think of is to simulate the parameters in A, and call B's main function directly. But it's not quite convenient. Is there any simple & direct way?

Thanks in advance for any suggestions.

Answer 1

Don't start a different process using the process builder; if you need A and B's main methods to run concurrently, you can use Threads.

public class A {
    public static void main(String[] args) {
        Thread bThread = new Thread(new Runnable() {
            public void run() {
                B.main(args);
            }
        });
        bThread.start();
        // Doing something for A
    }
}

public class B {
    public static void main(String[] args) {
        // Doing something for B
    }
}

Starting separate processes for Java is generally a bad idea as you can run everything in the same process. There are limited use-cases where it is still applicable but since you haven't provided a rationale for starting a process, I think you didn't know about being able to use Threads.