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That and also the JVM is a marvel of engineering with millions of hours that were poured in by smart people over the last 30 years.

It can be as fast a C, supports a multitude of languages, introspection, surveillance etc.

JFR is one of my favorite things about the JVM. Such good tooling to figure out whatever it is you are having problems with in production.

I've also used Eclipse MAT to find tricky dangling references to objects that caused memory leaks. Definitely not as polished, but extremely useful.

I agree JFR is amazing.

Also that you can start it on a running JVM and it that is has minimal ~1% performance overhead.