Fatal exceptions not caught in onErrorDropped Hook about reactor-core

[chemicL]

We can't do much in case of JVM fatal exceptions. There was at some point the logging handler added, that's why you see these logs. However, please refer to Simon's response and related discussions in that issue to understand more. Long story short, we can't handle Errors like Exceptions and propagate them via Reactor's mechanisms. You have to resort to traditional JVM control structures if you want to catch any Error. That is not recommended though and you should allow your JVM to exit as there might be no more memory left to even try to do any cleanup. External control is applicable - e.g. sizing your heap properly, responding to health checks (e.g. using Spring Boot Actuator's endpoint) and restarting the JVM using your orchestrator of choice (e.g. Kubernetes) if there's no timely response to the health checks.

[ResoluteError]

Thanks for the explanation and immediate response - totally makes sense. Indeed using JVM controls via -XX:+ExitOnOutOfMemoryError works fine when encountering actual OOM errors. Much appreciated. :)