## Abstract Classes (38) <https://www.youtube.com/watch?v=hZ1EU-F-0nU> * What is an abstract class? * How do we show an abstract class in a UML diagram? * Why can't you have a private abstract method? * What happens if you instantiate an abstract class? ## Java Interfaces (40) <https://www.youtube.com/watch?v=fX1xNMBTMfg> * What is an interface? * Give some examples of interface you've used * is a, has a or does? * How do we show an interface in a UML diagram * What's the difference between an interface and an abstract class?