1/ What is exposing an API? Basically, you are offering an access to your business logic through an Interface (the API), with full control on what you want to show or not.

What does it mean to expose data?

Data exposure is when data is left exposed in a database or server for anyone to see. Sensitive data can be exposed when configuration details for systems and applications are left unsecured online.

What does exposing a method mean?

It's called exposing a method when we make it public to other classes because we are doing just that. We are letting other classes know of it's existence and we're taking it out of hiding.