Why there are no OutOfMemoryError subclasses?

Question

As we all know, there are multiple reasons of OutOfMEmoryError (see first answer). Why there is only one exception covering all these cases instead of multiple fine-grained ones inheriting from OutOfMEmoryError?

Answer 1

I'd expect because you really can't do anything else when that happens: it almost doesn't matter WHY you ran out, since you're screwed regardless. Perhaps the additional info would be nice, but...

I know tomcat tries to do this "Out Of Memory Parachute" thing, where they hold onto a chunk of memory and try and release it, but I'm not sure how well it works.

Answer 2

The garbage collection process is deliberately very vaguely described to allow the greatest possible freedom for the JVM-implementors.

Hence the classes you mention are not provided in the API, but only in the implementation.

If you relied on them, your program would crash if running on a JVM without these vendor-specific sub-classes, so you don't do that.