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

Yet another solution on IntelliJ Ultimate 2018.2

• Hover over the import marked red
• Select dropdown arrow on the popup that appears on left (below)
• Choose "Add library ... to classpath"