Abstract classes and interfaces in Java serve fundamentally different purposes. Learn the differences between these Java language elements and how to use them in your programs.

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.

Languages such as Java and Kotlin, which have a C and C++ heritage, use lower camel case for variables and methods, and upper camel case for reference types such as enums, classes and interfaces.