# luaj/luaj

Lightweight, fast, Java-centric Lua interpreter written for JME and JSE, with string, table, package, math, io, os, debug, coroutine & luajava libraries, JSR-223 bindings, all metatags, weak tables and unique direct lua-to-java-bytecode compiling.

Repository: https://github.com/luaj/luaj
Canonical: https://ross.abutalabs.com/products/luaj
Homepage: http://luaj.sourceforge.net/
Language: Java
License: MIT
License Family: permissive
Topics: lua, java, jvm, scripting, scripting-language
Last push: 2023-04-24T08:10:39+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": 4024, "days_push": 1227, "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 1046, forks 182 (observed 2026-08-28T04:03:21.805006+00:00)

## What it is
Luaj is a lightweight, fast Lua interpreter (Lua 5.2.x compatible) written entirely in Java for JME, JSE, and JEE environments. It includes standard Lua libraries, JSR-223 scripting bindings, LuaJava API support, and unique direct Lua-to-Java-bytecode compilation.

## Use cases
- embed a Lua scripting engine in a Java application
- run Lua scripts on the JVM without native dependencies
- expose Java objects to Lua scripts via luajava
- use Lua as a JSR-223 pluggable scripting language
- compile Lua source directly to Java bytecode for performance
- sandbox user-written scripts inside a Java server

## When to choose
- you need Lua scripting embedded in a Java or JVM project
- you want a pure-Java, dependency-free Lua interpreter
- you need JSR-223 scripting integration or Lua-to-Java interop

## When to avoid
- you need full Lua 5.3/5.4 language features
- you need C Lua performance or C API compatibility
- you need an actively developed interpreter with frequent updates

## Facets
- artifact type: library
- maturity: maintenance
- function: interpreter, programming-language, sdk
- domain: programming-languages, developer-tools
- platform: jvm, cross-platform
- tags: lua, lua-vm, scripting-engine, jsr-223, bytecode-compilation, luajava, interpreters, scripting

## Member repositories
- luaj/luaj (main) score 23

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:21.805006+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 2026-08-30T07:01:58.003597+00:00, confidence not recorded.
  - readme: https://github.com/luaj/luaj (fetched 2026-08-28T04:03:21.805006+00:00, sha fcb480094001)
  - homepage: http://luaj.sourceforge.net/ (fetched 2026-08-29T13:02:41.270583+00:00, sha fd7f6082040f)
  - site_page: https://sourceforge.net/about (fetched 2026-08-29T13:02:41.279864+00:00, sha 47a5f3730d75)
  - site_page: https://sourceforge.net/p/forge/documentation/Docs%20Home (fetched 2026-08-29T13:02:41.281782+00:00, sha 3cca19403dfa)
  - site_page: https://sourceforge.net/about/leadership (fetched 2026-08-29T13:02:41.283553+00:00, sha bfffa8fdd816)
- Data as of 2026-08-30T08:39:29.467469+00:00.