[mike_hearn]

Bear in mind that the underlying protocol used to request hot swap on Java is a lot more expressive than the standard HotSpot implementation is. If you use the Jetbrains Runtime (a fork of OpenJDK) or the GraalVM "Espresso" VM (a.k.a. Java on Truffle) then you can do way more hotswapping than you'd be able to normally.

Espresso goes further and doesn't only allow hot swapping but lets you write plugins that react to hot swaps of code:

https://www.graalvm.org/latest/reference-manual/java-on-truf...

If you use the Micronaut web framework then it will selectively re-initialize your app in response to hot swaps that need it. Pretty advanced stuff.

[DanielHB]

That is pretty neat, I haven't done serious Java development in ~10 years but I do vaguely remember hot swapping would eventually cause out of memory errors. I was using standard OpenJDK 6 and 7 at the time.