Introduction

In today’s rapidly evolving AI landscape, integrating large language models (LLMs) like Claude into custom applications has become increasingly important. One powerful way to create this integration is through the Model Control Protocol (MCP), which allows applications to communicate with AI models in a standardized way. This blog post will guide you through the entire process of setting up an MCP Server application using Spring Boot and Java, and connecting it to the Claude desktop application.

By the end of this tutorial, you’ll have a functional MCP Server that allows Claude to interact with your local file system, specifically to explore directories on your desktop. This is just one example of how MCP can extend Claude’s capabilities beyond its standard features.

Prerequisites

Before we begin, let’s ensure you have all the necessary prerequisites:

Basic knowledge of Java programming
Basic understanding of Spring Boot framework
A computer running Windows, macOS, or Linux
Internet connection for downloading software and dependencies

Installing Java Development Kit (JDK)

The first step in our journey is to install the Java Development Kit (JDK), which provides the necessary tools to develop Java applications.

Download JDK

Visit the official Oracle website at https://www.oracle.com/java/technologies/downloads/ or alternatively, download OpenJDK from https://adoptium.net/
Select the appropriate JDK version for your operating system (we recommend JDK 17 or higher for Spring Boot applications)
Download the installer package

Install JDK

Windows Installation

Run the downloaded installer (.exe file)
Follow the installation wizard instructions
Accept the license agreement and choose the installation location
Complete the installation process
Press your Windows Key and go to Enviroment Variables
Press "Advanced"
Below System Variables, select "New"
Create a new variable called JAVA_HOME, and point it to your JDK location, which usually is in this directory: C:\Program Files\Java\jdk-yourjdkversion

macOS Installation

Open the downloaded .dmg file
Run the package installer
Follow the on-screen instructions to complete the installation

Linux Installation

For Debian/Ubuntu-based distributions:

sudo apt update
sudo apt install openjdk-17-jdk

For Red Hat/Fedora-based distributions:

sudo dnf install java-17-openjdk-devel

Verify Java Installation

To verify that Java has been installed correctly, open a terminal or command prompt and run:

java -version
javac -version

You should see output similar to:

java version "17.0.7" 2023-04-18 LTS
Java(TM) SE Runtime Environment (build 17.0.7+8-LTS-224)
Java HotSpot(TM) 64-Bit Server VM (build 17.0.7+8-LTS-224, mixed mode, sharing)

Installing IntelliJ IDEA

While you can use any IDE for Java development, we’ll use IntelliJ IDEA for this tutorial as it provides excellent support for Spring Boot applications.

Download IntelliJ IDEA

Visit the JetBrains website at https://www.jetbrains.com/idea/download/
Choose between the Community (free) or Ultimate (paid) edition
Download the appropriate version for your operating system

Install IntelliJ IDEA

Windows Installation

Run the downloaded .exe file
Follow the installation wizard
Select the installation location and additional components (e.g., 64-bit launcher, .java file association)
Click Install and wait for the process to complete

macOS Installation

Open the downloaded .dmg file
Drag the IntelliJ IDEA icon to the Applications folder

Linux Installation

Extract the downloaded .tar.gz file
```
tar -xzf ideaIC-*.tar.gz -C /opt/
```
Run the installation script
```
cd /opt/idea-*/bin
    ./idea.sh
```

Installing Claude Desktop

Next, we need to install the Claude desktop application, which will connect to our MCP Server.

Download Claude Desktop

Visit the official Anthropic website at https://www.anthropic.com/claude
Locate the Claude desktop application download section
Download the appropriate version for your operating system

Install Claude Desktop

Windows Installation

Run the downloaded installer
Follow the installation prompts
Complete the installation process

macOS Installation

Open the downloaded .dmg file
Drag the Claude icon to the Applications folder

Linux Installation

Follow the specific installation instructions provided on the download page for Linux.

Set Up Claude Account

Launch the Claude desktop application
Sign in with your Anthropic account or create a new account
Complete any initial setup steps required by the application

Creating a Spring Boot MCP Server Application

Now that we have all the necessary tools installed, let’s create our Spring Boot MCP Server application.

Generate a Spring Boot Project

Open your web browser and navigate to https://start.spring.io/
Configure your project with the following settings:
- Project: Maven
- Language: Java
- Spring Boot: 3.2.0 (or the latest stable version)
- Group: com.example (or your preferred group ID)
- Artifact: mcpserver
- Name: mcpserver
- Description: MCP Server for Claude integration
- Package name: com.example.mcpserver
- Packaging: Jar
- Java: 17 (or your installed version)
Add the following dependencies:
- Spring Web
- Spring MCP Server
Click on "Generate" to download the project as a ZIP file

Import the Project into IntelliJ IDEA

Extract the downloaded ZIP file to a location of your choice
Open IntelliJ IDEA
Click on "Open" or "Import Project"
Navigate to the extracted project folder and select it
Choose to open as a project
Wait for IntelliJ to import and index the project

Configure the MCP Server Application

Now, let’s configure our Spring Boot application to function as an MCP Server. We’ll need to create the main application class and a service that will provide tools for Claude to interact with.

Main Application Class

Create the main application class or modify the generated one to include the following code:

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.mcp.callback.*;

@SpringBootApplication
public class McpServerApplication {

    public static void main(String[] args) {
        SpringApplication.run(McpServerApplication.class, args);
    }

    @Bean
    public ToolCallbackProvider toolCallbackProvider(FilesListService filesListService) {
        return MethodToolCallbackProvider
                .builder()
                .toolObjects(filesListService)
                .build();
    }

}

This class serves as the entry point for our Spring Boot application. The ‘toolCallbackProvider‘ bean configures the MCP Server to use our ‘FilesListService‘ as a tool provider.

Files List Service

Next, create a new Java class called ‘FilesListService.java‘ with the following code:

import org.springframework.mcp.callback.annotation.Tool;
import org.springframework.mcp.callback.annotation.ToolParam;
import org.springframework.stereotype.Service;
import java.io.File;

@Service
public class FilesListService {

    private static final String DEFAULT_DIRECTORY = System.getProperty("user.home") + "\\Desktop";

    @Tool(description = "Explore a specific directory")
    public String[] listFiles(@ToolParam(description = "The specific folder that you want to explore on the desktop") String folderName) {
        File directory = new File(DEFAULT_DIRECTORY + "\\" + folderName);
        if (directory.exists() && directory.isDirectory()) {
            return directory.list();
        } else {
            return new String[]{"Directory not found: " + folderName};
        }
    }

    @Tool(description = "Explore the desktop")
    public String[] exploreDesktop() {
        File directory = new File(DEFAULT_DIRECTORY);
        return directory.list();
    }

}

This service provides two tools:

‘exploreDesktop‘: Lists all files and directories on your desktop
‘listFiles‘: Lists all files and directories within a specific folder on your desktop

Application Properties

Create or modify the ‘application.properties‘ file in the ‘src/main/resources‘ directory:

spring.application.name=mcpserver
spring.main.bannerMode=off
logging.pattern.console=

As noted in the code snippet, we turn off the banner and logging to avoid interfering with the standard I/O that MCP uses for communication.

Building and Running the MCP Server

Now that we have set up our MCP Server application, let’s build and run it.

Build the Application

Open a terminal or command prompt
Navigate to your project directory
Build the application using Maven:
```
./mvnw clean package
```
Or on Windows:
```
mvnw.cmd clean package
```

Alternatively, you can build the application directly from IntelliJ IDEA:

Open the Maven tool window (View > Tool Windows > Maven)
Expand your project
Double-click on "Lifecycle > package"

Run the Application

You can run the application in several ways:

Using the JAR File

java -jar target/mcpserver-0.0.1-SNAPSHOT.jar

Using Maven

./mvnw spring-boot:run

Using IntelliJ IDEA

Right-click on the ‘McpServerApplication‘ class
Select "Run ’McpServerApplication.main()’"

Connecting Claude to the MCP Server

Now that our MCP Server is running, let’s connect Claude to it.

Configure Claude to Use MCP

Open the Claude desktop application
Go to Settings (usually found in the menu or profile section in the top left corner)
Look for MCP or Extensions settings
Click on File - Settings
Click on Developer - Edit Config
Configure the MCP Client to connect to your local server by adding this code snippet:

        {
          "mcpServers": {
            "spring-ai-mcp-files": {
              "command": "java",
              "args": [
                "-Dspring.ai.mcp.server.stdio=true",
                "-jar",
                "/ABSOLUTE/PATH/TO/PARENT/FOLDER/mcpserver-0.0.1-SNAPSHOT.jar"
              ]
            }
          }
        }

Save the settings

Testing the Integration

To test if Claude can now access your MCP Server’s tools:

Start a new conversation with Claude
Ask Claude to list the files on your desktop
Example: "Can you show me what files are on my desktop?"
Claude should use the ‘exploreDesktop‘ tool and return a list of files and directories
Try asking Claude to explore a specific folder on your desktop
Example: "Can you list the files in my Documents folder on the desktop?"
Claude should use the ‘listFiles‘ tool with the parameter "Documents" and return the contents of that directory

Extending the MCP Server

Now that you have a basic MCP Server working with Claude, you can extend it with additional functionality. Here are some ideas:

Add File Reading Capability

You could add a tool that reads the content of text files:

@Tool(description = "Read the content of a text file")
public String readTextFile(
    @ToolParam(description = "The path to the file relative to the desktop") 
    String filePath) {
    try {
        Path path = Paths.get(DEFAULT_DIRECTORY, filePath);
        return Files.readString(path);
    } catch (IOException e) {
        return "Error reading file: " + e.getMessage();
    }
}

Add Image Processing Capabilities

You could add tools that process images on your desktop:

@Tool(description = "Get metadata from an image file")
public Map<String, String> getImageMetadata(
    @ToolParam(description = "The path to the image file relative to the desktop") 
    String imagePath) {
    // Implementation for extracting image metadata
}

Add Database Integration

You could connect your MCP Server to a database and provide tools for Claude to query it:

@Tool(description = "Execute a SQL query")
public List<Map<String, Object>> executeQuery(
    @ToolParam(description = "The SQL query to execute") 
    String sqlQuery) {
    // Implementation for safe query execution
}

Best Practices and Security Considerations

When developing an MCP Server, keep these best practices in mind:

Security

Always validate and sanitize inputs from Claude to prevent security vulnerabilities
Restrict file access to specific directories to prevent unauthorized access
Use proper exception handling to avoid exposing sensitive information
Consider adding authentication if your MCP Server will be accessible over a network

Performance

Optimize your tools for performance, especially when dealing with large files or databases
Consider implementing caching for frequently accessed data
Use asynchronous operations for long-running tasks

Usability

Provide clear and descriptive tool names and parameter descriptions
Return meaningful error messages that Claude can understand and relay to the user
Structure the output of your tools in a way that’s easy for Claude to process and present

Troubleshooting

Here are some common issues you might encounter and how to resolve them:

Connection Issues

If Claude can’t connect to your MCP Server:

Ensure your MCP Server is running
Check that the path to your JAR file is correct in Claude’s settings
Verify that your Java version is compatible with your application
Check for firewall or antivirus software that might be blocking the connection

Tool Execution Issues

If tools aren’t working as expected:

Check the console output of your MCP Server for errors
Ensure that your tool methods have the correct annotations
Verify that the parameters are correctly defined
Test your tools with simple test cases before integrating with Claude

Conclusion

In this comprehensive guide, we’ve walked through the entire process of setting up an MCP Server application using Spring Boot and Java, and connecting it to Claude. We’ve covered everything from installing the necessary tools to implementing and testing the integration.

By following this guide, you’ve learned how to:

Install Java and IntelliJ IDEA
Set up the Claude desktop application
Create a Spring Boot project with MCP Server support
Implement tools for Claude to interact with your file system
Connect Claude to your MCP Server
Test the integration
Extend your MCP Server with additional functionality

This is just the beginning of what you can do with MCP and Claude. By creating custom tools tailored to your specific needs, you can significantly enhance Claude’s capabilities and create powerful, integrated AI solutions.

Additional Resources

To learn more about the technologies used in this tutorial, check out these resources:

Spring Boot Documentation: https://docs.spring.io/spring-boot/docs/current/reference/html/
Claude Documentation: https://docs.anthropic.com/
Java Documentation: https://docs.oracle.com/en/java/
IntelliJ IDEA Documentation: https://www.jetbrains.com/idea/documentation/