Every now and then, my IDEA seems to forget what files are in my project, and I have to remove and readd a source folder in project settings. Is there a way to figure out why it does this?
I just had an issue dealing adding a custom object to an arraylist of a file I was working on and it was saying "cannot access ___." Removing source folder in project settings and re adding it fixed it. But I had to do it earlier as it was not letting my main class be runnable.