Java implementation for Min-Max Heap?

Question

Do you know of a popular library (Apache, Google, etc, collections) which has a reliable Java implementation for a min-max heap, that is a heap which allows to peek its mini

Answer 1

Instead of a max-min heap, could you use two instances of a java.util.PriorityQueue containing the same elements? The first instance would be passed a comparator which puts the maximum at the head, and the second instance would use a comparator which puts the minimum at the head.

The downside is that add, delete, etc would have to be performed on both structures, but it should satisfy your requirements.