ai4j

Java 8+ agentic SDK: unified LLM access (OpenAI/Anthropic/DashScope/Doubao/DeepSeek...), Tool Calling, MCP, RAG, Agent Runtime, and a built-in Coding Agent CLI/TUI/ACP. Maintained by LnYo-Cly on GitHub, where it has earned 422 stars from the community.

It's actively developed around chatgpt, java, openai, and is a solid reference for anyone building with these tools.