01 hello world

Module 01: Hello World

Your first Claude Agent SDK program.

What You’ll Learn

• How to add the SDK dependency to your project
• The simplest way to query Claude: Query.text()
• Running a query and getting a text response

Prerequisites

1. Claude CLI installed and authenticated

   npm install -g @anthropic-ai/claude-code
   claude login
   

2. Java 21 or later

The Code

import org.springaicommunity.claude.agent.sdk.Query;

public class HelloWorld {
    public static void main(String[] args) {
        // One line - that's it!
        String answer = Query.text("What is 2 + 2?");
        System.out.println(answer);
    }
}

Source Code

View on GitHub

Running the Example

mvn compile exec:java -pl module-01-hello-world

How It Works

1. Query.text() is a static method that takes a prompt string
2. It starts the Claude CLI as a subprocess
3. Sends your prompt to Claude
4. Returns Claude’s text response as a String
5. The CLI subprocess exits automatically

Key Points

• Stateless: Each Query.text() call creates a new session
• Blocking: The call waits for Claude’s complete response
• Simple: No configuration required for basic usage

Next Module

Module 02: Query API - Learn about Query.execute() for getting response metadata like cost and token usage.