spring-bootmodel-context-protocolspring-aiclaudeclaude-desktop

MCP Server Connection Error - "Server disconnected" when connecting Java-based server to Claude Desktop

I'm trying to create a Java-based MCP server following this tutorial, but I'm getting a "Server disconnected" error when attempting to connect it to Claude Desktop.

Environment

Configuration

Claude Desktop MCP Configuration (claude_desktop_config.json)

{
  "mcpServers": {
    "fran-mcp": {
      "command": "/Users/myname/.sdkman/candidates/java/current/bin/java",
      "args": [
        "-jar",
        "/Users/myname/IdeaProjects/mcp-server/target/mcp-server-0.0.1-SNAPSHOT.jar"
      ]
    }
  }
}

Application Properties

spring.application.name=mcp-server
server.port=8081

spring.ai.mcp.server.name=fran-mcp
spring.main.web-application-type=none
spring.ai.mcp.server.version=0.0.1

# Disable banner and console logging for STDIO transport
spring.main.banner-mode=off
logging.pattern.console=

Maven Dependencies

<dependency>
    <groupId>org.springframework.ai</groupId>
    <artifactId>spring-ai-starter-mcp-server-webmvc</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <scope>runtime</scope>
    <optional>true</optional>
</dependency>
 <dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>

Error Details

The server appears to start successfully but disconnects immediately after the initialization message:

2025-08-23T20:57:11.518Z [fran-mcp] [info] Server started and connected successfully
2025-08-23T20:57:11.522Z [fran-mcp] [info] Message from client: {"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"claude-ai","version":"0.1.0"}},"jsonrpc":"2.0","id":0}

2025-08-23T20:57:19.192Z [fran-mcp] [info] Server transport closed
2025-08-23T20:57:19.194Z [fran-mcp] [info] Server transport closed unexpectedly, this is likely due to the process exiting early
2025-08-23T20:57:19.194Z [fran-mcp] [error] Server disconnected

Thank you.

Solution

  • Changed the dependency from

    <dependency>
    <groupId>org.springframework.ai</groupId>
    <artifactId>spring-ai-starter-mcp-server-webmvc</artifactId>
</dependency>

    to

    <dependency>
    <groupId>org.springframework.ai</groupId>
    <artifactId>spring-ai-starter-mcp-server</artifactId>
</dependency>

    and it's working now after regenerating the jar and restarting Claude Desktop.