Ranked by how they treat first pull requests
The most beginner-friendly Java open source projects
Projects that merge pull requests from outside contributors and answer them quickly: the two things a newcomer cannot see before sending one.
-
1. ShaftHQ/SHAFT_ENGINE Java
Java test automation framework for web, mobile, API, CLI, database, and desktop E2E testing with a fluent API and built-in reporting.
97% of outside PRs merged Maintainers usually reply within 1 day
1 open beginner issue 410 stars
-
2. hiero-ledger/hiero-mirror-node Java
Hiero Mirror Node archives data from consensus nodes and serves it via an API
94% of outside PRs merged Maintainers usually reply within 1 day
3 open beginner issues 186 stars
-
3. Netflix/spectator Java
Client library for collecting metrics.
100% of outside PRs merged Maintainers usually reply within 1 day
1 open beginner issue 767 stars
-
4. vaadin/testbench Java
Vaadin TestBench is a tool for automated user interface testing of Vaadin applications.
100% of outside PRs merged Maintainers usually reply within 1 day
3 open beginner issues 25 stars
-
5. quarkiverse/quarkus-mcp-server Java
This extension enables developers to implement the MCP server features easily.
96% of outside PRs merged Maintainers usually reply within 1 day
1 open beginner issue 201 stars
-
6. redhat-developer/lsp4ij Java
LSP & DAP Client for IntelliJ
100% of outside PRs merged Maintainers usually reply within 1 day
3 open beginner issues 344 stars
-
Artifactory permissions synchronization tool and data set
89% of outside PRs merged Maintainers usually reply within 1 day
5 open beginner issues 98 stars
-
8. wso2/product-is Java
Welcome to the WSO2 Identity Server source code! For info on working with the WSO2 Identity Server repository and contributing code, click the link below.
84% of outside PRs merged Maintainers usually reply within 1 day
33 open beginner issues 880 stars
-
9. IBM/universal-connectors Java
A collection of Universal connector plug-ins for IBM Guardium Data Protection and IBM Guardium Insights. A universal connector allows Guardium customers to digest data activity events from various ...
91% of outside PRs merged Maintainers usually reply within 1 day
1 open beginner issue 28 stars
-
10. awslabs/amazon-kinesis-client Java
Client library for Amazon Kinesis
100% of outside PRs merged Maintainers usually reply within 1 day
1 open beginner issue 668 stars
-
11. eclipse-edc/Connector Java
EDC core services including data plane and control plane
100% of outside PRs merged Maintainers usually reply within 1 day
1 open beginner issue 426 stars
-
Generated Java code for Google APIs
82% of outside PRs merged Maintainers usually reply within 1 day
1 open beginner issue 725 stars
-
13. finos/rune-dsl Java
The project containing the Rune DSL grammar and default code generators
92% of outside PRs merged Maintainers usually reply within 1 day
1 open beginner issue 49 stars
-
14. Automattic/simplenote-android Java
Simplenote for Android
83% of outside PRs merged Maintainers usually reply within 1 day
3 open beginner issues 1,911 stars
-
15. openrewrite/rewrite Java
Automated mass refactoring of source code.
83% of outside PRs merged Maintainers usually reply within 1 day
3 open beginner issues 3,736 stars
-
16. vaadin/flow Java
Vaadin Flow is a Java framework binding Vaadin web components to Java. This is part of Vaadin 10+.
84% of outside PRs merged Maintainers usually reply within 1 day
6 open beginner issues 755 stars
-
17. testng-team/testng Java
TestNG testing framework
95% of outside PRs merged Maintainers usually reply within 1 day
5 open beginner issues 2,059 stars
-
18. deepjavalibrary/djl Java
An Engine-Agnostic Deep Learning Framework in Java
83% of outside PRs merged Maintainers usually reply within 1 day
3 open beginner issues 4,856 stars
-
19. micronaut-projects/micronaut-openapi Java
Generates OpenAPI / Swagger Documentation for Micronaut projects
100% of outside PRs merged Maintainers usually reply within 1 day
2 open beginner issues 114 stars
-
20. quarkusio/skills Java
Agent skills for developing and maintaining Quarkus applications
92% of outside PRs merged Maintainers usually reply within 1 day
2 open beginner issues 36 stars
How this ranking works
Score = merge rate × reply speed. The merge rate is the share of pull requests from outside contributors (anyone who is not an owner, member or collaborator of the project, bots excluded) merged in the last 30 days, smoothed as (merged + 1) ÷ (sent + 2) so a few lucky merges do not outrank a long record. The reply speed is 1 ÷ (1 + the median number of days before a pull request gets its first reply from someone other than its author, or is merged). Bot comments do not count as replies.
Listed: projects with at least 10 outside pull requests in that window, at least one open beginner issue, at least 10 stars, a push in the last 180 days, not archived, and measured in the last 30 days.