# greenrobot/essentials

General purpose utilities and hash functions for Android and Java (aka java-common)

Repository: https://github.com/greenrobot/essentials
Canonical: https://ross.abutalabs.com/products/greenrobot-essentials
Language: Java
License: Apache-2.0
License Family: permissive
Last push: 2021-03-22T07:44:57+00:00

## Health v2 (maintenance only)
Score: 23/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 4320, "days_push": 1990, "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 1349, forks 188 (observed 2026-08-28T04:04:27.863399+00:00)

## What it is
A lightweight collection of general-purpose utility classes for Java and Android, including primitive long-key hash collections, multimaps, an object cache, IO/file/string/date helpers, and a fast Murmur3 hash implementation. It aims to outperform standard Java APIs while staying under 100k in size.

## Use cases
- use fast hash maps and sets with primitive long keys in Java
- get a Murmur3 hash implementation faster than the JDK's
- cache objects with weak/soft references and time-based expiration in Android
- store multiple values per key with a multimap
- read and write files and streams with less boilerplate
- split and join strings efficiently
- replace heavyweight dependencies like Guava with a tiny utility library

## When to avoid
- you need the breadth of Guava or Apache Commons
- you need a framework rather than a small utility set
- you need actively maintained code with recent releases

## Facets
- artifact type: library
- maturity: maintenance
- function: caching, serialization, developer-tools
- domain: developer-tools, android-tools, performance
- platform: jvm
- tags: java-utilities, hash-functions, primitive-collections, murmur3, multimap, object-cache, io-utilities, lightweight, algorithms, android

## Member repositories
- greenrobot/essentials (main) score 23

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:27.863399+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 2026-08-30T04:42:21.788526+00:00, confidence not recorded.
  - readme: https://github.com/greenrobot/essentials (fetched 2026-08-28T04:04:27.863399+00:00, sha e246bfe89362)
- Data as of 2026-08-30T08:39:29.467469+00:00.