Intellij idea not understanding JDK or not seeing it?

Question

IntelliJ IDEA

Intellij idea not understanding JDK or not seeing it? But the code compiles fine.
Here Intellij highlights almost everything that is, saying they don’t understand and don’t know.



and he auto-tips say they say it's normal, we see everything, but as soon as we complete the input, the input will turn red again.

if we look at the options for fixing the problem, it all comes down to this,

but the JDK is already up and running initially, this appeared after a reboot

Answer 1

Apparently there is only one solution to this problem. Reinstall Intellij IDEA with removal of all IDE settings and configurations