Encapsulation Encapsulation is the mechanism of hiding of data implementation by restricting access to public methods. Abstraction Abstract means a concept or an Idea which is not associated with any particular instance. Using abstract class/interface we express the intent of the class rather than the actual implementation. In a way, one class should not know the inner details of another in order to use it, just knowing the interfaces should be good enough. Inheritance Inheritances expresses "is a" relationship between two objects. Using proper inheritance, In derived classes we can reuse the code of existing super classes. Polymorphism It means one name many forms. It is further of two types - static and dynamic. Static polymorphism is achieved using method overloading and dynamic polymorphism using method overriding.