# eclipse-openj9/openj9

Eclipse OpenJ9: A Java Virtual Machine for OpenJDK that's optimized for small footprint, fast start-up, and high throughput.   Builds on Eclipse OMR (https://github.com/eclipse/omr) and combines with the Extensions for OpenJDK for OpenJ9 repo.

Repository: https://github.com/eclipse-openj9/openj9
Canonical: https://ross.abutalabs.com/products/openj9
Language: Java
License: NOASSERTION
License Family: other
Topics: java, jvm, eclipse-openj9, compiler, garbage-collector, gc, jit, interpreter, runtime, virtual-machine, hacktoberfest
Last push: 2026-08-26T22:29:31+00:00

## Health v2 (maintenance only)
Score: 94/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 83, longevity 100
- inputs: {"age_days": 3295, "days_push": 7, "days_rel": 34, "gap_med": 47.5, "n_releases_24m": 13}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3537, forks 792 (observed 2026-08-28T04:08:09.095117+00:00)

## What it is
Eclipse OpenJ9 is an independent, enterprise-grade Java Virtual Machine implementation for OpenJDK, built on Eclipse OMR. It is optimized for small memory footprint, fast startup, and high throughput.

## Use cases
- run Java applications with lower memory footprint
- reduce JVM startup time for containers and serverless
- replace HotSpot with an alternative OpenJDK JVM
- tune garbage collection for high-throughput workloads
- contribute to or study JVM internals

## When to choose
- memory or startup cost matters, e.g. containers, microservices, cloud
- you want an alternative JVM backed by Eclipse and IBM
- you need AOT compilation or OpenJ9-specific GC options

## When to avoid
- you need maximum ecosystem compatibility and tooling tuned for HotSpot
- your team has no capacity to handle a less common runtime
- you rely on HotSpot-specific flags or JVM features

## Facets
- artifact type: application
- maturity: active
- function: interpreter, compiler
- domain: programming-languages, performance, developer-tools
- platform: windows, cross-platform, jvm
- tags: jvm, java-virtual-machine, openjdk, jit-compiler, garbage-collection, eclipse-omr, linux, macos

## Member repositories
- eclipse-openj9/openj9 (main) score 94

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:09.095117+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 2026-08-29T18:35:01.981923+00:00, confidence not recorded.
  - readme: https://github.com/eclipse-openj9/openj9 (fetched 2026-08-28T04:08:09.095117+00:00, sha daeb8e061b0a)
- Data as of 2026-08-30T08:39:29.467469+00:00.