Bukkit

Minequery 1.5
Minequery creates a small server that listens for requests and responds with the port of Minecraft server, the current amount of players online, the max players cap, and the entire player list.

In the past, Minecraft did not have a query protocol and as a result Minequery was created to fulfill the need for a query protocol. Today, this plugin has been replaced with the query protocol that now exists in Minecraft.

Where do I get Minequery?
Version 1.5 of Minequery can be downloaded from here.
The source code of Minequery can be found on GitHub.

How do I install Minequery?
Just copy Minequery.jar into your plugins directory.

Configuring Minequery
There is one configurable option for Minequery that can be placed in server.properties:

minequery-port=25566

minequery-port is the port on which the query server runs on. The default port is 25566.

How do I query servers say from my own server list or my own site?
Currently there is a plugin for Ruby on Rails and a class file for PHP.

If you are code savvy, you'll want to issue this request to the query server:

QUERY

The query server should respond with something like this:

SERVERPORT 25565
PLAYERCOUNT 0
MAXPLAYERS 20
PLAYERLIST []

Since 1.3, you can additionally issue a request for a JSON response to the query server:

QUERY_JSON

The query server will respond with a JSON string:

{"serverPort":25565,"playerCount":0,"maxPlayers":20,"playerList":[]}

How can I contribute?
For starters, you can fork the plugin on GitHub.
Additionally you can create unofficial libraries in different languages for sites to query servers with.

Troubleshooting
If you are having problems, please see the troubleshooting page.

Changelog
1.5 - February 25, 2011
- Changed TSLPC to a default constructor for Bukkit build #415.

1.4 - February 21, 2011
- Fixed an issue where the server port was mistakenly reporting the port of the Minequery server.

1.3 - February 20, 2011
- Removed the shutdown exception. It is now a more friendly message.
- Added QUERY_JSON for JSON queries.
- Minequery now binds to the same IP as the Minecraft server (reads the "server-ip" property).

1.2 - January 23, 2011
- Fixed a null pointer exception on an invalid query. Thanks to daze for the heads up.
- Threaded request handling. Minequery will now respond to multiple connections at once without blocking.
- Added console messages for on enable and on disable.

1.1 - January 20, 2011
- Updated for build #66.

1.0 - January 6, 2011
- First version.