Its not automatic, you need to explicitly release. They are referring to the tools builtin in xcode which you will have to use manually to debug memory problems in Objective-C then move it back to your Java code as annotations.
I think that's referring to "development runtime", not "production runtime". I.e. run a memory leak detector while you are debugging and profiling. But once you fix all/most of the leaks, you don't need to deploy a GC.
So... a garbage collector?