Without any more information, it's hard to know exactly what you want. However, when choosing what data structure to use, you need to take into account what you need it for. Hashmaps are not designed for sorting - they are designed for easy retrieval. So in your case, you'd probably have to extract each element from the hashmap, and put them into a data structure more conducive to sorting, such as a heap or a set, and then sort them there.
