FYI - I had a discussion the the Core-Libs-Dev mailing list several months ago. I had done some crude testing where I found walking the stack in Java 9 didn't seem to perform too well. The Open JDK devs were recommending that StackWalker be used to capture the immediate caller, not walk the stack trace from the bottom. I haven't gotten back to this yet so I'd be very interested in your findings.