How do you integrate LangChain4j with Spring Boot?

LangChain4j provides a dedicated Spring Boot starter (langchain4j-spring-boot-starter) that wires everything up through standard Spring Boot auto-configuration. You add the starter plus the provider-specific starter for your chosen LLM, drop configuration into application.properties, and Spring automatically creates the ChatLanguageModel, EmbeddingModel, and related beans that you can inject anywhere in the application.

<!-- pom.xml -->
<dependency>
    <groupId>dev.langchain4j</groupId>
    <artifactId>langchain4j-spring-boot-starter</artifactId>
    <version>0.32.0</version>
</dependency>
<dependency>
    <groupId>dev.langchain4j</groupId>
    <artifactId>langchain4j-open-ai-spring-boot-starter</artifactId>
    <version>0.32.0</version>
</dependency>

# application.properties
langchain4j.open-ai.chat-model.api-key=${OPENAI_API_KEY}
langchain4j.open-ai.chat-model.model-name=gpt-4o
langchain4j.open-ai.chat-model.temperature=0.7
langchain4j.open-ai.embedding-model.api-key=${OPENAI_API_KEY}

For AI Services specifically, Spring Boot integration uses the @AiService annotation (or you declare a @Bean manually). LangChain4j detects annotated interfaces during component scan and creates Spring-managed proxy beans — meaning the AI service is injectable like any other Spring component:

@AiService
interface CustomerSupportAgent {
    @SystemMessage("You are a helpful customer support agent.")
    String chat(String userMessage);
}

@RestController
class SupportController {
    private final CustomerSupportAgent agent;
    SupportController(CustomerSupportAgent agent) { this.agent = agent; }

    @PostMapping("/support")
    String support(@RequestBody String message) {
        return agent.chat(message);
    }
}

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