Why so red? IntelliJ seems to think every declaration/method cannot be found/resolved
IntelliJ sometimes gets confused all by itself, even without the external changes Korgen described (though that is a good way to consistently reproduce it).
Click File -> Synchronize, and IntelliJ should see that everything is okay again.
If that doesn't work, IntelliJ's caches might be corrupt (this used to happen a lot more often than it does now); in that case, regenerate them by
Clicking File -> Invalidate Caches and restarting the IDE
(though loading the project will take a while while the caches are recreated).
I experienced this when I updated my JDK manually and removed the previous JDK
Solution
- In the IntelliJ editor, click on the red keyword (
Integer
for example) and press ALT + ENTER (or click the light bulb icon) - select Setup JDK from the intentions menu
- click on
Configure
- In my case, the JDK path was incorrect (pointed on
/opt/jdk1.7.0_51
instead of/opt/jdk1.7.0_65
)
- Click on the ... and browse to the right JDK path
- Let's clear the cache:
And everything should be back to life :)
IntelliJ sometime gets confused after importing maven projects and then changing poms externally or generating sources outside IntelliJ.
You might want to try a maven->force reimport from within intellij on the project root