by polymorphism,inheritance,abstraction,encapsulation

Encapsulation,Inheritance,Polymorphism are OOPS principles.

In Java, these OOPS principles are achieved as follows:

Encapsulation & data hiding is achieved thru access modifiers

Inheritance is achieved thru Interfaces

Polymorphism is achieved thru overloading of methods

1) Encapsulation:- is achieved through
classes.(Binding/Storing data and methods as a single unit )
2) Abstraction:-it is achieved through private, protected,
public, default keywords.
3)Inheritance through interfaces.
4)polymorphism is achieved through method overloading and
constructor overloading.
5)Message Passing -through objects calling

1)using Classes & Interfaces