There are two main ways of deploying Confluence inside IDEA. The main reason you would want to is so that you can debug your plugins.
Confluence Source
This is the preferred of the two, since it will allow you to step through Confluence code as well as your own plugin code when debugging. However, it is only available if you have a source code license, which generally only comes with a full Commercial license.
Confluence Distribution
The other way is to get a regular Confluence distribution running inside IDEA. This works just fine, but you won't be able to step into code outside your own plugin.
