This compilation unit is not on the build path of a Java project

Question

When I try to use ctrl+space this error is shown:

This compilation unit is not on the build path of a Java project.

I see tha

Answer 1

In my case, I have Eclipse Maven project. I had the same issue and I posted detailed explanation of the issue and answer here Eclipse Maven - Code Completion fails "This compilation unit is not on the build path of a Java project" and "Failed to Download Index" Error