# ethereum/ethereumj

DEPRECATED! Java implementation of the Ethereum yellowpaper. For JSON-RPC and other client features check Ethereum Harmony

Repository: https://github.com/ethereum/ethereumj
Canonical: https://ross.abutalabs.com/products/ethereumj
Language: Java
License: LGPL-3.0
License Family: copyleft
Archived: true
Last push: 2022-02-24T15:16:54+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 4495, "days_push": 1651, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2183, forks 1071 (observed 2026-08-28T04:06:23.420319+00:00)

## What it is
EthereumJ is a pure-Java implementation of the Ethereum protocol as defined in the yellow paper, usable as a Maven/Gradle dependency or standalone JAR. The project is officially deprecated and no longer maintained, with JSON-RPC client features moved to Ethereum Harmony.

## Use cases
- embed ethereum protocol support in a java application
- run an ethereum node from the jvm
- interact with the ethereum blockchain in java
- build blockchain tools on top of the ethereum protocol
- learn how the ethereum yellow paper is implemented

## When to choose
- you need a java/jvm library implementing the ethereum protocol for a legacy codebase
- you want to study a reference implementation of the ethereum yellow paper

## When to avoid
- you need an actively maintained ethereum client
- you need JSON-RPC or full client features (use Ethereum Harmony or other clients)
- you are starting a new project today

## Facets
- artifact type: library
- maturity: abandoned
- function: sdk, cryptography, networking
- domain: blockchain, developer-tools
- platform: jvm, cross-platform
- tags: ethereum, blockchain-client, deprecated, yellowpaper, smart-contracts, cryptocurrency

## Member repositories
- ethereum/ethereumj (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:23.420319+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 2026-08-30T02:48:14.852488+00:00, confidence not recorded.
  - readme: https://github.com/ethereum/ethereumj (fetched 2026-08-28T04:06:23.420319+00:00, sha 5963887a2c96)
- Data as of 2026-08-30T08:39:29.467469+00:00.