Implements vs extends: When to use? What's the difference?

Question

Please explain in an easy to understand language or a link to some article.

Answer 1

A class can only "implement" an interface. A class only "extends" a class. Likewise, an interface can extend another interface.

A class can only extend one other class. A class can implement several interfaces.

If instead you are more interested in knowing when to use abstract classes and interfaces, refer to this thread: Interface vs Abstract Class (general OO)