carrotsearch/hppc

Health v2 · maintenance only

Adoption not part of the score

1052 stars · 166 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

HPPC (High Performance Primitive Collections) is a Java library providing maps, sets, lists, and stacks of primitive types, tuned for maximum performance and memory efficiency. It intentionally deviates from the java.util.collections API, exposing open internals to avoid boxing overhead.

Use cases

• store primitive types without autoboxing overhead in Java
• reduce memory footprint of large collections of ints or longs
• high-performance hash maps and sets for primitives
• replace java.util collections in performance-critical code
• implement fast data structures for search and indexing engines

When to choose

• your Java code is bottlenecked by boxing and GC pressure from java.util collections
• you need memory-efficient primitive maps, sets, lists, or stacks
• you are comfortable with a non-standard API in exchange for performance

When to avoid

• you need java.util.Collection compatibility or standard APIs
• you prefer convenience and rich APIs over raw performance
• your collections are small and performance is not a concern

Facets

library · maturity stable

data-science developer-tools performance developer-tools jvm primitive-collections memory-efficiency java-collections high-performance data-structures algorithms

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