6_java_standalone

Standalone Java MCP Server

This example is structured like a user-owned Java project. It has its own easyp.yaml, Gradle build, protobuf contract, generated source directory, and stdio MCP server.

Generate

make generate

easyp.yaml does two jobs:

• resolves mcp/options/v1/options.proto through deps
• runs Java protobuf generation plus protoc-gen-mcp with lang=java

The proto is Java-native and intentionally does not declare go_package. protoc-gen-mcp synthesizes the internal metadata that protogen needs for lang=java.

with_imports: true is used so the local mcp.options.v1 Java extension class is generated from the Easyp dependency. The build removes generated com.google.protobuf sources afterward and uses the protobuf Java jar for Google runtime classes.

The local repository version uses:

command: ["go", "run", "../../cmd/protoc-gen-mcp"]

In an external project, replace it with the released plugin binary or module entrypoint you want to pin.

Build And Run

make build
make run

The server registers generated tools through:

TodoMcp.registerTodoAPITools(transportProvider, new Handler(), "todo");

The generated source lives under src/generated/main/java after generation. The handwritten server lives under src/main/java and implements the generated TodoMcp.TodoAPIToolHandler interface.