# jbox2d/jbox2d

a 2d Java physics engine, native java port of the C++ physics engines Box2D and LiquidFun

Repository: https://github.com/jbox2d/jbox2d
Canonical: https://ross.abutalabs.com/products/jbox2d
Homepage: http://www.jbox2d.org
Language: Java
License: BSD-2-Clause
License Family: permissive
Last push: 2024-09-19T18:39:46+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 4623, "days_push": 713, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1147, forks 216 (observed 2026-08-28T04:03:45.971456+00:00)

## What it is
JBox2d is a native Java port of the C++ Box2D and LiquidFun 2D physics engines, providing rigid body simulation, joints, continuous collision detection, and LiquidFun particle physics. It includes a serialization module and a testbed framework for running physics demos.

## Use cases
- simulate 2d rigid body physics in a java game
- add gravity and collision detection to a jvm application
- run liquid particle fluid simulation in java
- port box2d physics to android or gwt web
- test 2d physics scenarios with a testbed framework

## When to choose
- you need a mature, permissively licensed 2D physics engine on the JVM
- you want Box2D/LiquidFun behavior with Java-native code
- you're targeting Android, desktop, or browser (via GWT/TeaVM) with Java

## When to avoid
- you need 3D physics
- you need cutting-edge performance or active feature development
- you're not on the JVM

## Facets
- artifact type: library
- maturity: maintenance
- function: simulation, graphics, game-engine, serialization
- domain: simulation, graphics
- platform: jvm, cross-platform, browser
- tags: physics-engine, box2d, liquidfun, rigid-body-physics, particle-simulation, gwt, collision-detection, game-development

## Member repositories
- jbox2d/jbox2d (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:45.971456+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 2026-08-30T06:34:02.633610+00:00, confidence not recorded.
  - readme: https://github.com/jbox2d/jbox2d (fetched 2026-08-28T04:03:45.971456+00:00, sha 4b2c907181dd)
  - homepage: http://www.jbox2d.org (fetched 2026-08-29T12:39:14.261991+00:00, sha e5ccabe46309)
- Data as of 2026-08-30T08:39:29.467469+00:00.