Show a minimal amount of code, so we see what you do with HashMap.

Thanks a lot for your reply as usual, PhiLho. Here's how I fixed this problem: I don't know exactly why Processing throws an ambiguity error when I'm using the complete name for the conflicting object, but if you happen to be in this situation, you can fix it by importing the class directly from the Java library (correct me if any of the terminology here is wrong), by placing this at the beginning of the code:

Well, I thought you had this from the start. That's why I ask for (simple) code...
I don't see how it resolved your problem with iterator, and it won't lift the ambiguity of the two declarations (ie. you still have to give the fully qualified name for one of them) but as long as it works for you...
Perhaps you need an internal definition of Map, namely Map.Entry.