# carrotsearch/hppc

High Performance Primitive Collections for Java

Repository: https://github.com/carrotsearch/hppc
Canonical: https://ross.abutalabs.com/products/hppc
Homepage: http://labs.carrotsearch.com
Language: Java
License: Apache-2.0
License Family: permissive
Last push: 2026-08-13T19:58:21+00:00

## Health v2 (maintenance only)
Score: 66/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 97, release rhythm 8, longevity 100
- inputs: {"age_days": 5671, "days_push": 20, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1052, forks 166 (observed 2026-08-28T04:03:23.326616+00:00)

## What it is
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
- artifact type: library
- maturity: stable
- function: data-science, developer-tools
- domain: performance, developer-tools
- platform: jvm
- tags: primitive-collections, memory-efficiency, java-collections, high-performance, data-structures, algorithms

## Member repositories
- carrotsearch/hppc (main) score 66

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:23.326616+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:59:42.414620+00:00, confidence not recorded.
  - readme: https://github.com/carrotsearch/hppc (fetched 2026-08-28T04:03:23.326616+00:00, sha 628a13d0da41)
  - homepage: http://labs.carrotsearch.com (fetched 2026-08-29T13:01:01.275520+00:00, sha 289b20bfdad6)
  - site_page: http://labs.carrotsearch.com/about.html (fetched 2026-08-29T13:01:01.284850+00:00, sha 9965771934e0)
- Data as of 2026-08-30T08:39:29.467469+00:00.