kencopas/JavaSampleMCP

Java Sample MCP Server

This repository provides a minimal Java sample implementation of an MCP (Model Context Protocol) server.
It is intended for anyone who wants to:

• Clone the project
• Run a small example server that exposes a synchronous tool
• Extend the functionality to implement their own tools and behavior

Features Included

• A small Java application (com.example.Application) that starts an MCP server using the SDK and a stdio transport provider.
• A built-in sync tool named get_presentations which returns a list of sample presentations.
• A Presentation record and PresentationTools helper class containing example data and simple lookup methods.

Requirements

• Java 21
• Maven

Build and Run

1. Clone the repository.

2. Build the project with Maven:

   mvn clean package
   

3. Run the shaded JAR produced in target:

   java -jar target/gson-demo-1.0-SNAPSHOT.jar
   

The server is configured to use standard input/output as the transport.
Use an MCP-capable client or a simple wrapper that communicates via STDIO to call the exposed tool(s).

Setup MCP Server with GitHub Copilot

You can use GitHub Copilot to interact with the MCP server.

Open mcp.json

• IntelliJ IDEA:
  Open the GitHub Copilot chat window → click the toolset icon → Add MCP Tools → this will open the mcp.json file.

• Visual Studio Code:
  Open the command palette (Ctrl+Shift+P or Cmd+Shift+P on Mac) → type MCP: Open User Configuration → select it to open the mcp.json file.

Add Custom MCP Server

Once inside mcp.json, add the following configuration:

{
  "servers": {
    "custom-mcp": {
      "command": "java",
      "args": [
        "-jar",
        "C:\\path\\to\\gson-demo-1.0-SNAPSHOT.jar"
      ]
    }
  }
}

👉 Replace the path with the actual location of your built JAR file.

After saving, click the toolset icon again — you should now see your custom-mcp server and the get_presentations tool available.

MCP Inspector

To use the MCP Inspector with this server:

1. Make sure Node.js is installed.

2. Run:

   npx @modelcontextprotocol/inspector
   

This launches the MCP Inspector in your browser.
Set:

• Command → java
• Arguments → -jar path/to/gson-demo-1.0-SNAPSHOT.jar

Once connected, you can run tools, resources, and prompts, and view input/output schemas.

Extending the Sample

• Add new tools:
  Edit Application.java to register additional SyncToolSpecification or other SDK-supported features.

• Change or extend data:
  Update PresentationTools.java to load data from files, a database, or an external API.

• Customize serialization:
  The project currently uses Gson as an example. You can replace or configure the ObjectMapper used by the transport provider.

Notes

• This sample is intentionally small — it demonstrates wiring the SDK, a transport, and a simple tool.
  It is not production-ready.

• Dependencies include the MCP SDK and SLF4J (simple logger) as declared in pom.xml.