# LangChain4j — LLM Integration for Java

> LangChain4j integrates 20+ LLM providers and 30+ vector stores into Java apps. 11.4K+ stars. Unified API, RAG, MCP, Spring Boot. Apache 2.0.

## Install

Save the content below to `.claude/skills/` or append to your `CLAUDE.md`:

## Quick Use

```xml
<!-- Maven -->
<dependency>
    <groupId>dev.langchain4j</groupId>
    <artifactId>langchain4j</artifactId>
    <version>1.0.0</version>
</dependency>
```

```java
ChatLanguageModel model = OpenAiChatModel.withApiKey("sk-...");
String answer = model.chat("Hello!");
```

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## Intro

LangChain4j is an open-source Java library for integrating LLMs into Java applications. With 11,400+ GitHub stars and Apache 2.0 license, it provides a unified API across 20+ LLM providers and 30+ embedding/vector stores, comprehensive toolbox (prompt templating, chat memory, function calling, agents, RAG), MCP support, and seamless integration with Spring Boot, Quarkus, Helidon, and Micronaut.

**Best for**: Java developers building AI-powered enterprise applications
**Works with**: Claude Code, OpenAI Codex, Cursor, Gemini CLI, Windsurf

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## Key Features

- 20+ LLM providers unified API
- 30+ vector/embedding stores
- Function calling and MCP support
- RAG patterns built in
- Spring Boot, Quarkus, Helidon, Micronaut
- Prompt templating and chat memory

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### FAQ

**Q: What is LangChain4j?**
A: Java LLM library with 11.4K+ stars. 20+ providers, 30+ vector stores, RAG, MCP, Spring Boot. Apache 2.0.

**Q: How do I install LangChain4j?**
A: Add Maven dependency dev.langchain4j:langchain4j.

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## Source & Thanks

> [langchain4j/langchain4j](https://github.com/langchain4j/langchain4j) — 11,400+ GitHub stars

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Source: https://tokrepo.com/en/workflows/f7069ed9-81bd-4e67-a727-44e37eb529e7
Author: Skill Factory