Why so red? IntelliJ seems to think every declaration/method cannot be found/resolved

Question

I just installed and re-installed IntelliJ. Every Java file is coming up RED. I checked the JDK; it is at 1.6.##. The maven clean install build worked just fine

Answer 1

I had the same issue I was using JDK 1.9 with IntelliJ 14, I solved reinstalling Java with latest version of JDK 1.8(1.8.0_161 in this case)

I also removed the 1.9 version from

HKEY_CURRENT_USER\Software\JavaSoft\JRE\Security Baseline