MCP Javadc MCP Server

Model Context Protocol (MCP) server for Java decompilation

Local serverstdio

What is the MCP Javadc MCP server?

MCP Javadc MCP server is a locally run integration for AI assistants that speak the Model Context Protocol. Model Context Protocol (MCP) server for Java decompilation.

What you get

A Model Context Protocol (MCP) server for decompiling Java class files. This server allows AI assistants and tools that implement the MCP protocol to decompile Java bytecode into readable source code.

  • Decompile Java .class files from file path
  • Decompile Java classes from package name (e.g., java.util.ArrayList)
  • Decompile Java classes from JAR files
  • Specify which class to extract from JAR files
  • Full MCP-compatible API
  • Stdio transport for seamless integration

Configuration and credentials

You will need one environment variable: CLASSPATH. Keep credentials in your client's env block or a secrets manager rather than in a file you might commit.

  • Node.js 16+ - npm - No Java requirement (using JavaScript port of CFR decompiler)

Setting it up

Installation goes through your MCP client rather than a global install: point it at without on npm and it is fetched when the client starts. The copy-paste blocks for Claude Desktop, Claude Code and Cursor are further down this page.

Choosing this one

This sits in the developer tooling group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. It is maintained by idachev; worth a glance at recent repository activity before you build anything load-bearing on it.

This entry was verified against MCP Javadc's own documentation before publication; SyncDev keeps the directory reviewed rather than auto-generated.

Before you rely on it

  • It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
  • MCP clients confirm each tool call by default. Leave that on until you have watched what the mcp javadc mcp server does with a few real requests.

How to install the MCP Javadc MCP server

Example MCP client configuration:

```json
{
  "mcpServers": {
    "javaDecompiler": {
      "command": "npx",
      "args": ["-y", "@idachev/mcp-javadc"],
      "env": {
        "CLASSPATH": "/path/to/java/classes"
      }
    }
  }
}

Configuration as documented by the project. Restart the client after saving.

Configuration

  • Node.js 16+ - npm - No Java requirement (using JavaScript port of CFR decompiler)
VariableDescriptionRequired
CLASSPATHFilesystem location the server is allowed to use.Optional

Frequently asked questions

It connects MCP Javadc to MCP-compatible AI assistants such as Claude and Cursor. Instead of copying data back and forth by hand, the assistant works with MCP Javadc directly.