Simple Definitions in ABAP Objects

Definition of Class:
A Class is a Template of objects which can handle more than one characteristics .
A class donot have any data it has attributes and methods.

Definition of Objects:
Object is an realtime entity in the world.
It is the instances on classes and hold some data.

Definition of Association:
Relating two classes or relation between two classes is called as Association.

Definition of Aggregation:
One class using the instances on other classs is know as Aggregation.

Definition of Composition:
When one class data is related or will affect other class data is known as composition
Eg:when one class data is deleted the data pertaining to that in another class will be deleted.

Definition of Abstraction:
Extracting the essential details or data while ignoring the unwanted data.

Definition of Encapsulation:
Enclosing all parts of Abstraction in a container. It is often know as Information Hiding
Hides how information how the implementation is done.shows only the necessary information.