Koloboke Implementation Library

An implementation of the Koloboke Collections API.

Compatibility with the Java Collections Framework

  • Fail-fast semantics everywhere
  • null keys are (optionally) supported, just like in java.util.HashMap
  • Float.NaN and Double.NaN keys are treated consistently with boxed version (all NaNs are considered equal)


Here are several performance/memory footprint comparisons (covering different use cases) of collections frameworks, evidencing that in most cases Koloboke implementation library is the fastest and the most memory efficient library implementing hash maps and sets, typically beating the closest competitor by a large margin:

The only thing that is faster than the Koloboke implementation library is Koloboke Compile.

The library is fat

The major disadvantage of the Koloboke implementation library is that it is very fat, total size of it’s jars with dependencies is almost 20 MB. Koloboke Compile is much thinner.

Quick start

To start with the Koloboke implementation library,  read the Quick start section on Github.