test code for saving-restoring mach ports: https://github.com/dkimitsa/codesnippets/tree/master/MachExceptionSaveRestoreTest

This looks great :)

I have one question, according to your original post on crash reporters, Signals.installSignals(...) was needed as otherwise a caught exception (such as the NPE in the example code) would result in the application being terminated. However in my tests, using Signals.installSignals or not didn't seem to make any difference. The behaviour was exactly the same. Any idea why ?

In case of crashlytics it play nice and calls previous handler which is robovm one. But there was some crash reporters that were callung abort() once they received sigabort. For example this was happening with appdynamics. And signal.installSignal was just for sake processing signals before aggressive sdks

Interesting. Thanks for your answer!

Important to mention that even if reporter just observes signal and passes it to parrent, without signal.installSignal it will catch all robovms npe and report them as crashes. So approach still valid

Thanks, it's appreciated!