lightweight-component/aj-mcp

AJ-MCP 一个轻量级Java MCP SDK

AJ-MCP 是一个轻量级的 Java 模型上下文协议（MCP）SDK。它提供了一个小巧直接的 API 用于构建 MCP客户端和服务器，尤其是对于必须保持Java的现有系统 8 或 Spring Boot 2.x。

• 支持 Java 8 及以上版本，支持 Spring Boot 2.x。
• 轻量级且体积小巧，主要依赖于 Jackson JSON 和 OkHttp。
• 易于使用和扩展，配有示例和双语文档。
• 支持 STDIO、遗留的 HTTP/SSE 传输和可流式 HTTP。
• 实现MCP协议修订版2024-11-05、2025-03-26和2025-06-18，并通过版本协商实现。
• 涵盖工具、资源、资源模板、提示、完成、分页、订阅、取消、日志记录， 根、采样和引发。

看看这三个MCP SDK组件项目：

独立的 AJ MCP Next 项目在使用 AJ Util 的 Java 8 上针对 2026-07-28。 它拥有核心/客户端/服务器模块，带有 STDIO 和无会话 HTTP 适配器，与这个遗留 SDK 分开。

• AJ MCP Common，AJ-MCP 的通用库，包含模型上下文的实现 协议及其他常见内容

AJ-MCP A Lightweight Java MCP SDK

AJ-MCP is a lightweight Model Context Protocol (MCP) SDK for Java. It provides a small, direct API for building MCP clients and servers, especially for existing systems that must remain on Java 8 or Spring Boot 2.x.

• Supports Java 8 and above, and supports Spring Boot 2.x.
• Lightweight and small, with Jackson JSON and OkHttp as its main runtime dependencies.
• Easy to use and extend, with examples and bilingual documentation.
• Supports STDIO, the legacy HTTP/SSE transport, and Streamable HTTP.
• Implements MCP protocol revisions 2024-11-05, 2025-03-26, and 2025-06-18 with version negotiation.
• Covers tools, resources, resource templates, prompts, completion, pagination, subscriptions, cancellation, logging, roots, sampling, and elicitation.

Check out these three projects of MCP SDK components:

The independent AJ MCP Next project targets 2026-07-28 on Java 8 using AJ Util. It has core/client/server modules with STDIO and sessionless HTTP adapters, separate from this legacy SDK.

• AJ MCP Common, Common library for AJ-MCP, it contains the implementation of the Model Context Protocol and some other common classes.
• AJ MCP Client, MCP Client SDK.
• AJ MCP Server, MCP Server SDK.
• Samples for both client and server.
• Spring Streamable HTTP sample, with a dedicated StreamableHttpClientExample in samples/client (Java 8).

For further information, please refer to the User Manual website.

When to use AJ-MCP

AJ-MCP is intended for Java applications that need to expose existing business capabilities to AI clients, or consume MCP servers without upgrading the entire application stack. Typical uses include:

• wrapping an existing Java service as MCP tools, resources, or prompts;
• connecting a Java desktop or server application to a local STDIO MCP process;
• integrating MCP into Spring Boot 2.x or a Servlet-based application;
• supporting clients that negotiate different MCP protocol revisions.

JSON-RPC batch messages are intentionally not supported.

Modules