That's one of the things I like about the Java ecosystem. The tooling is very mature. Heap dump analysis is easy and being able to connect to a live JVM, either using JMX/remoting, Thermostat or Oracle's Java Mission Control, makes it almost painless and easy, almost, to look at your JVM internals and see what bottlenecks you might be hitting.

I don't know how to get the same kind of information on Ruby, Python or node.js but I'm pretty sure it might involve some gdb and debug symbols. No idea.