com.github.vsonnier:hppcrt (maven): High Performance Primitive Collections Realtime (fork of HPPC from Carrotsearch) Fundamental data structures (maps, sets, lists, queues, heaps, sorts) generated for combinations of object and primitive types to conserve JVM memory and speed up execution. The Realtime fork intends to extend the existing collections, by tweaking to remove any dynamic allocations at runtime, and to obtain low variance execution times whatever the input nature. 
Keywords: hppc|hppcrt|java-5|no-dependencies|realtime|retrolambda