Describe what an Interface is and how it’s different from a Class?

Purpose:

• This question is positioned by Scott as a Mid-Level question but in reality it should apply to juniors too.
• It is a basic teaser question to see if a developer has developed anything more sophisticated than a simple application. A lack of interface awareness or use could point to either a developer being very junior or being a code-by-google kind of single point developer that has a low level of understanding of what they are actually doing.

Potential Answer:
Interface defines a contract and does not have any executable code of its own. Class is concrete implementation representing single concept that can inherit from single parent and can implement multiple interfaces.