Abstract Data Types

Abstract data type is a theoretical concept, a collection of function signatures and rules to describe the values that a type can have by defining how these values will be constructed.

The Collection in Java is a framework that provides an architecture to store and manipulate the group of objects and is known as java collection framework. Java collection framework provides the set of classes and interfaces. The Collection interface extends Iterable interface and Collection is the route interface of all interfaces that extends it and these interfaces are further implemented by classes.

Think of an Abstract Data Type as a picture of data and operation to manipulate and change it. And Data Structure as real, concrete thing that can implement and used with the algorithm.

Think List as an Abstract Data type and the classes that implements it are the data Structure and provides its own implementation.