Eclipse error “Could not find or load main class”

Question

I know there are many duplicates of this question, but I have looked at them all, and none of them have solved the issue.

I am trying to run a class that has a main

Answer 1

Found This while searching, and it was after I updated my Java that the problem seemed to occur.

In Eclipse from your project:

Right-click on your project
Click Properties
Java build path: Libraries; Remove the "JRE System Library[J2SE 1.4]"
Click Add Library -> JRE System Library
Select the new "Execution Environment" or Workspace default JRE