Koloboke is a higher performance collections library that I have not seen around before. It has the usual primitive collections and claims to perform better than some of the other options out there (like Trove or HPPC). The collections implement the basic Set, Map, and Collection interfaces making them easier to integrate into your existing code.
[quote]and claims to perform better than some of the other options out there (like Trove or HPPC).
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Benchmarks: http://java-performance.info/large-hashmap-overview-jdk-fastutil-goldman-sachs-hppc-koloboke-trove/