Intellij IDEA: False positives on build

Question

I'm using Intellij IDEA for work on a Java project.

I'm finding I get a lot of false positives when I build in Intellij, but only when there are other compilation errors - eg I've made a change and expect a number of compile errors, so I build to find all the errors. (In this instance, I changed a widely used interface, and want the compiler to catch the errors so that I know which implementations to fix.) In addition to some of these expected errors, Intellij reports hundreds of false positives (which makes it difficult to find the real errors - at present the compiler is showing only one genuine compile error each time, so I have to rebuild to find the next error...). These false compile errors are not highlighted - indeed, they are not real compile errors. (Nor do they appear if I compile via Maven.)

The most common error is 'cannot find symbol class [X]', despite that class often being in the same project.

I've tried: - upgrading Intellij (from 10.5.1 to 10.5.2 to 11.0.1) - invalidating and rebuilding caches - restarting Intellij ...but all to no effect.

I've searched the Intellij Bug Tracking board , but haven't found any reference to this there, so wondered whether this is user error (if so, what settings do I need to change)?

Has anyone else experienced anything like this? If so, how did you fix it?

Answer 1

This is probably too late to help you, but maybe it will help somebody else. I had a similar problem. IntelliJ complained that it couldn't find a symbol class, and the class it couldn't find had an icon with a little x in the upper left hand corner. The x indicates that the class was excluded from compilation. (I have no idea how that happened.)

To include the excluded file, access project settings, eg, by clicking Ctrl+Alt+S. Then you can modify the list found under Project Settings -> Compiler -> Excludes, to re-include the excluded file.

Answer 2

Such issue can be caused by incorrect project configuration, like when some module source directories are added to the dependencies as library roots. If you can't find a problem yourself, either contact support or file a bug to YouTrack with a sample project attached and the steps to reproduce the problem.