Eclipse Inspect(Ctrl+shift+I) not working

Question

I checked out a maven project in Eclipse and am unable to Inspect a Variable (right click on the variable and click Inspect option).

When I attempt to do so, I get the

Answer 1

I got the same error message.

To solve that "Debug Configuration" >> {{JAVA_DEBUG_APPLICATION_NAME}} >> Source (tab)

Check the source is added correctly,

For me,

1. while debugging the java code it opens the class file, which should not be edited.
   
2. got the error message too,

I have removed the sources from the source tab, It solved both the problem