Comparable and (Treet) obj in IDEA from Java Data Structure

I've been using IntelliJ IDEA to write all the code that we do here. Whenever I completed my code in Workspaces it compiled and ran like expected at the end of Java Data Structure video.

However when I pasted said code on IDEA it's giving me an error. 2 in fact

1) public class Treet implements Comparable{} gives an error that states that class Treet needs to be declared as abstract or I need to implement the abstract method compareTo(T). Which we did in this video.

2)inside the compareTo(Objects obj){} method I get an error when we cast Treet other = (Treet) obj;

it says "Inconvertible types; cannot cast java.util.Objects to com.teamtreehouse.Treet" which I'm guessing it's what's giving the error #1

Now this code works in workspaces but it won't compile in IDEA which obviously means that it's something specific to IDEA.

Does anyone know what the problem is? or why is IDEA giving out this error?