At a guess, is your code and imports have errors all over it like this?
If so, your error isn’t that it can’t override from the super class, but it can’t find the superclass, so it isn’t aware that it’s supposed to be overriding a method from the super class.
With errors in programming if you have multiple errors, the compiler and IDE can get confused very very quickly, generally fix the first error you see first, until you get skilled enough to recognize what the real errors are.
To fix this you need to fix your project setup, you said that you are trying to target minecraft 1.10.2? For that you will need to compile against SpongeAPI 5.0.0-SNAPSHOT
The easiest way to set this up in my opinion, is to use the MinecraftDev intellij plugin.
this will allow you to have a set up project very very quickly.