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a2aproject/a2a-java

Official Java SDK for the Agent2Agent (A2A) Protocol

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a2aproject/a2a-java has 500+ stars and 150+ forks on GitHub, is written in Java, and was last pushed on Oct 18, 2026. Data as of . Signed-in members get hourly updates — create a free account.

Summary Information

Updated 1 hour ago
Type:Library / SDKCategory(s):Agent Frameworks & SDKsAPIs, GraphQL & RPCAI Agents & LLM Apps
Added to GitGenius on October 15th, 2026
Created on May 2nd, 2025
Open Issues & Pull Requests: 76 (+0)
GitHub issues: Enabled
Number of forks: 186
Total Stargazers: 505 (+0)
Total Subscribers: 10 (+0)

Repository Insights (GitGenius)

Median issue/PR response: 43.6 hours
Mean response time: 15.1 days
90th percentile: 43.4 days
Tracked items: 370

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Maintainer activity

12 people did triage or write work on this repository in the last 12 months.

Counts unlabeled, assigned, unassigned, milestoned, demilestoned, locked, unlocked over the last 12 months. These are issue and pull request events that require triage or write permission. Commits and code review are not counted. labeled and renamed are excluded because GitHub issue forms record the issue author as the actor. Figures from October 18, 2026. This count is not comparable across projects: each project's automation decides which of these events a person emits. How this is counted.

How this project is maintained

About 8% of issues opened in the past year have never received a reply. 75% of open issues come from outside the core team, so the backlog reflects real-world use rather than internal planning. Work labelled "compatibility" is answered fastest, typically in about 6 hours, while "server" waits about 2 weeks. 52% of tracked open issues have had no activity in three months. 83% of issues opened in the past year have been closed, leaving a working backlog.

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Issue Activity (beta)

Open issues: 52
New in 7 days: 9
Closed in 7 days: 2
Avg open age: 215 days
Stale 30+ days: 35
Stale 90+ days: 29

Recent activity

Opened in 7 days: 9
Closed in 7 days: 2
Comments in 7 days: 1
Events in 7 days: 8

Top labels

  • server (21)
  • compatibility (20)
  • good first issue (20)
  • wontfix (18)
  • client (17)
  • hacktoberfest (14)
  • priority: high (11)
  • http+json (7)

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Detailed Description

A2A Java SDK is an official Java library that helps run agentic applications as Agent2Agent (A2A) Protocol servers.

The tool addresses the need for Java applications to participate in agent-to-agent communication networks. It provides a multi-module Maven library supporting both client and server roles, with communication possible over JSON-RPC, gRPC, and REST transports. The approach follows the A2A Protocol specification, allowing Java agents to expose their capabilities and interact with other A2A-compliant agents regardless of their implementation language.

Developers should adopt this tool if they are building Java-based agentic applications that need to interoperate within A2A ecosystems. It suits projects ranging from simple agent services to complex distributed agent systems. The project includes reference implementations for Quarkus with JSON-RPC, gRPC, and HTTP+JSON transports, and integrations exist for Jakarta EE runtimes. Community-contributed integrations with other Java frameworks are supported through a documented contribution process. The tool requires Java 17 or later and is distributed as Maven modules for flexible dependency management.

The project maintains active development with regular updates to align with the A2A Protocol specification. The codebase includes regeneration tooling for gRPC protocol buffer files sourced from the upstream specification repository, indicating ongoing synchronization with protocol evolution. Documentation is comprehensive, covering server and client setup guides, API reference, community articles, and contribution guidelines. The project actively encourages community contributions through established integration patterns and maintains example implementations demonstrating both server and client usage patterns.