I have the following structure: HashMap< String, HashMap< String, String Now i want to know the last accessed element in the 2nd dimension. I know there is TreeMap which makes sense in the 1rst dimension but after that it doesn't make any sense. How can I keep track of a 2D HashMap ordering? With access i mean: value = hashmap.get("a").get("1") value = hashmap.get("b").get("2") value = hashmap.get("c").get("3") hashmap.removeLast(); hashmap.removeLast(); hashmap.removeLast();