Java: Sorted collection which allows duplicates, is memory efficient and provides fast insert + update

Question

Specifically I need a collection which uses one field A for accessing and a different one (field S) for sorting but a sorted collection which accepts duplicate would be suff

Answer 1

I have good experience with TreeMultimap https://guava.dev/releases/19.0/api/docs/com/google/common/collect/TreeMultimap.html