Looks like you want to find which polygon a point is inside off. I remember a similar question being asked recently. Maybe those two links help you out: Point in polygon - Wikipedia
In this thread there’s an implementation for the ray casting algorithm in R. It should be easy to adapt it for Java Snippets.
It should also not be too difficult to either loop over all polygons with a recursive loop or expand the algorithm to return the surrounding polygon within a single node.