[PaulHoule]

That reminds me of the time I debugged some code (also neural network) that was in both Java and C++ and I was able to attach both gdb and jdb to the same process but had to disable the segfault trap on gdb because the jvm segfaults all the time in normal operation.

[MereInterest]

As a C++ developer, I'm struggling to understand how and why segfaults would ever be part of normal operation. In my mental model, the presence of a segfault means that a program has gone so far off the expected path that no guarantees can be made about its state whatsoever, so the only safe thing to do is to let the program crash. Is there a reason why the JVM regularly segfaults?

[planede]

Segfaults are unexpected and shouldn't happen in a conforming C++ program that doesn't evaluate operations with undefined behavior.

But in non-portable C or C++ program doing manual memory management with OS primitives targeting a specific OS the conditions for segfault are well documented, and you can also rely on the programs behavior when that happens (the OS raises a signal for you, that you can handle).

There are not many programs that should be written this way, but I assume the JVM might fall into this category. I'm still not sure if handling page faults this way in regular operation is the best strategy, but I would worry about performance more than correctness.

[aa-jv]

A pretty good investigation into this matter - "segfaults in Java (redux)":

https://www.lukeshu.com/blog/java-segfault-redux.html

Read the prior article for some context, too ..

[PaulHoule]

I think Java catches the segfault and throws a NullPointerException or something like that.

[kelahcim]

Which reminds me that with IntelliJ you can get a really nice combo for debugging Java/C/C++ code: https://youtu.be/8Cjeq4l5COU