In this Java 101 tutorial, I’ve explained how interfaces differ from classes, and showed you how to declare, implement, and extend interfaces in your Java programs.

Java lets you declare interfaces inside of classes. Once declared, an interface is automatically a static member of the class. There is no need to declare the interface with the static keyword.

The abstract keyword can be used in different ways for writing java classes to implement abstraction. We can have: 1.An abstract class with one or more abstract method (s) ...