There are four concepts of OOPs(Object Oriented Programming System):
Process of Aquiring properties from one class to another without changes is known as Inheritance. In other word, the ability of a new class to be created, from an existing class by extending it, is called inheritance.
Abstraction reduces complexity by hiding non essancial details and showing only essancial details.
Wrapping up of data and methods in to a single unit is called as encapsulation.
The encapsulation is mainly achieved by creating classes, the classes expose public methods and properties. A class is kind of a container or capsule or a cell, which encapsulate a set of methods, attribute and properties to provide its indented functionalities to other classes.
Polymorphisms is a generic term that means 'many forms'. More precisely Polymorphisms means the ability to request that the same operations be performed by a wide range of different types of things.
The polymorphisms is achieved by using many different techniques named method overloading, operator overloading, and method overriding.