Re: "pointer stack instead of object stack"

So that change had a positive effect when you benchmarked it? I'd tend to call "pointer stack instead of object stack" an inaccurate way of thinking about it, because object references in Java are pointers under-the-hood.

I have a feeling that perhaps the performance gain you may have saw actually came from avoiding a pointer deference in "if(results.peekPrio() > pointRectDist((2*_dimensions)*nodeIndex,searchLocation))" as compared to "if(results.peekPrio() > searchNode.pointRectDist(searchLocation))"

Calls to private methods are inlined. Calls to public methods aren't. Object references and polymorphism are a lot harder for compilers to optimize.

Polymorphism overhead can usually be detected with profiling.