What is a good design or idea or utility to create a cache collection of N number of elements Least Recently Used?

[Vic Cekvenich]

What is a good design or idea or utility  to create a cache collection of N number of elements Least Recently Used?   Say a hash map with synchronized get and put, that would track LRU and lock at the element level? Must be of fixed size and work at element level.   Suggestion please and thanks in advance for any comments. Vic