If you have an n-tiered architecture, sometimes you have to modify every tier to add some functionality. If you are using a naming convention that standardizes names for the components of your component, IDEA makes it really easy to open up every file.
Let’s say you have the following files, likely located in several different packages:
EntityDAO EntityDAOOracle EntityDAOFactory EntityBean EntityAction EntityForm
To open all of these in one shot, CTRL-N and type Entity* to get the autocomplete list. Then press Shift+down arrow, highlight all the files, and press Enter
Voila! All your files are open.