An IntelliJ plugin to mark files as Plain Text. Can be useful when some files contain errors or when you don't intend them to be compiled. This will make sure you can still build your project.
Download the provided jar-file. Inside IntelliJ go to: File | Settings | Plugins, click Install plugin from disk... and find the jar-file inside of your file system. Lookup the plugin in your plugins list and make sure it is checked. Now you should be able to right-click a file (e.g. a java-file) and click Mark as Plain Text. To unmark it, just right-click the file again and go to Unmark as Plain Text.