OOPS CONCEPT IN JAVA
OOPS
- OOP means Object Oriented Programming.
- It organizes a program around its data,i.e.,objects and a set of well defined interfaces to that data.
- An object-oriented program can be characterized as data controlling access to code.This is a technique used to create programs around the real world entities.
- In OOPs programming model, programs are developed around objects and data rather than actions and logics.
- In OOPs, every real life object has properties and behavior.
- This feature is achieved in java through the class and object creation. They contains properties (variables of some type) and behavior (methods).
- OOPs provides better flexibility and compatibility for developing large applications.
- OOPS concept includes
- class,
- method,
- inheritance,
- encapsulation,
- abstraction,
- polymorphism etc.
Object
- Objects are key to understanding object-oriented technology.
- Examples of real-world objects: your dog, your desk, your television set, your bicycle.
- Real-world objects share two characteristics: They all have state and behavior. Dogs have state (name, color, breed, hungry) and behavior (barking, fetching, wagging tail).
- Identifying the state and behavior for real-world objects is a great way to begin thinking in terms of object-oriented programming.
Class
- It is the central point of OOP and that contains data and codes with behavior.
- In Java everything happens within class and it describes a set of objects with common behavior. The class definition describes all the properties, behavior, and identity of objects present within that class.
- As far as types of classes are concerned, there are predefined classes in languages like C++ and Pascal. But in Java one can define his/her own types with data and code.
Methods
- Class can define both attributes and behaviors.
- Again attributes are defined by variables and behaviors are represented by methods.
- In other words, methods define the abilities of an object.
Inheritance
- This is the mechanism of organizing and structuring software program.
- Though objects are distinguished from each other by some additional features but there are objects that share certain things common.
- In object oriented programming classes can inherit some common behavior and state from others.
- Inheritance in OOP allows to define a general class and later to organize some other classes simply adding some details with the old class definition.
- This saves work as the special class inherits all the properties of the old general class and as a programmer you only require the new features.
- This helps in a better data analysis, accurate coding and reduces development time.
Abstraction
- The process of abstraction in Java is used to hide certain details and only show the essential features of the object.
- In other words, it deals with the outside view of an object (interface).
Encapsulation
- This is an important programming concept that assists in separating an object's state from its behavior.
- This helps in hiding an object's data describing its state from any further modification by external component.
- In Java there are four different terms used for hiding data constructs and these are public, private, protected and package.
- As we know an object can associated with data with predefined classes and in any application an object can know about the data it needs to know about.
- So any unnecessary data are not required by an object can be hidden by this process.
- It can also be termed as information hiding that prohibits outsiders in seeing the inside of an object in which abstraction is implemented.
Polymorphism
- It describes the ability of the object in belonging to different types with specific behavior of each type.
- So by using this, one object can be treated like another and in this way it can create and define multiple level of interface.
- Here the programmers need not have to know the exact type of object in advance and this is being implemented at runtime.
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