# andreabergia/rjvm

A tiny JVM written in Rust. Learning project

Repository: https://github.com/andreabergia/rjvm
Canonical: https://ross.abutalabs.com/products/rjvm
Language: Rust
License: Apache-2.0
License Family: permissive
Last push: 2024-01-24T08:02:43+00:00

## Health v2 (maintenance only)
Score: 31/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 35, longevity 92
- inputs: {"age_days": 1299, "days_push": 952, "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 1578, forks 94 (observed 2026-08-28T04:05:06.677473+00:00)

## What it is
A minimal Java Virtual Machine (JVM 7) implemented in Rust as a hobby learning project. It can parse .class files, resolve classes from jars or folders, and execute simple Java programs using real OpenJDK 7 classes, including features like exceptions, garbage collection, and virtual/static methods.

## Use cases
- learn how a JVM works internally
- study a JVM implementation written in Rust
- execute simple Java bytecode without a full JVM
- understand Java class file format parsing
- learn Rust by reading a real interpreter codebase
- explore garbage collection and exception handling in a VM

## When to choose
- you want to read a small, approachable JVM implementation to learn VM internals
- you are learning Rust and want a real-world codebase to study
- you need to run very simple Java 7 programs for experimentation
- you want to follow a blog series explaining how to build a JVM from scratch

## When to avoid
- you need a production-ready JVM to run real applications
- you need threading, reflection, I/O, JIT compilation, or class file verification
- you need full Java compatibility or multi-dimensional arrays
- you need a well-tested, documented, or maintained tool

## Facets
- artifact type: application
- maturity: experimental
- function: interpreter, parser, programming-language
- domain: programming-languages, education, developer-tools
- platform: windows, rust
- tags: jvm, virtual-machine, rust, learning-project, java, bytecode, class-file-parser, garbage-collection, linux, macos

## Member repositories
- andreabergia/rjvm (main) score 31

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:06.677473+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 2026-08-30T03:56:54.507442+00:00, confidence not recorded.
  - readme: https://github.com/andreabergia/rjvm (fetched 2026-08-28T04:05:06.677473+00:00, sha 6ff1cd3119a5)
- Data as of 2026-08-30T08:39:29.467469+00:00.