This is a super minimal example of a bot that has two commands. To use this bot, you'll need the actual CanDoGram artifacts, which you can find here.
The /hello command takes no parameters and greets the user politely, then as a bonus sends the user a picture of a cat.
The /dice command takes one parameter of the form XdY, where X is a number representing how many dice should be rolled, and Y represents how many dice should be rolled.
This bot can be launched by deploying it into a Java EE compatible container. It's only been tested on WIldfly 13 though.
But it works fine.