Q:

How to make IntellijIDEA ignore work-in-progress class files? 

When I'm working in IntellijIDEA how do I tell it to ignore a class file that may have problems and I want to leave dormant for a while? 
It will throw errors when I compile whatever class I am working on until I fix the first "dormant" class.  
I have tried adding my class to a bogus package but Intellij doesn't like that either because the path doesn't match.   

A:

Settings | Compiler | Excludes, add your WIP files there:

A:

You could use Refactor -> Rename File..., and change the file extension. 

A:

That is set at the inspection level
Configure Current File Analysis CTRL + SHIFT + ALT + H
I have profiles with differing inspection levels setup loosely based on the phase of my project builds ... I'd suggest taking a look at Customizing Inspection Profiles.  

To ignore specific files during compilation you can add files individually or recursively in via the project settings panel ... 
Configure Compiler Analysis CTRL + ALT + S :: Compiler => Validation 

