How to debug Eclipse's internal clases

Question

I have a very strange problem with regards to contributing to Eclipse. I have modified bundle org.eclipse.jdt.internal.junit4.runner and just wanted to test it and try it, but for some strange reason my breakpoints in the bundle org.eclipse.jdt.internal.junit4.runner are not working. It sounds to me that there is an internal filtering that cause that these bundles are ignored for breakpoint.

Funny thing is when I add

System.err.println("Did you reach it?"); //$NON-NLS-1$

In the console I can see the text, but the breakpoint is not working...

Any advice would be very welcome.

Answer 1

Look here. Also check whether any packages are excluded in Windows->Preferences->Java->Debug->Step filtering.

Answer 2

Well, I found out the problem but not a complete answer.

The problem is especially related to the org.eclipse.jdt.internal.junit4.runner bundle which launches and an another virtual machine and the code within this VM is not in debug mode, e.g. the first virtual machine is in debug mode and the second is not and that was the reason why my breakpoints did not work. So I guess there is no possibility how to enable debug mode "by eclipse automatically" in the subsequent VMs.

Here is an example of 2 VM from my blog http://blog.chocolatejar.eu/contribution/2014/02/27/better-visualization-junit-failures/