• Chennai, Bangalore & Online: 93450 45466Coimbatore: 95978 88270Madurai: 97900 94102

  • OOPs In JAVA: Object Oriented Programming Concepts With Examples In Java

    In this, we understand the Object-Oriented Programming (OOP) paradigm of Java, deeply with this table of content…
    What is Object-Oriented Programming and Other Programming Paradigm
    Classes in Java
    Objects in Java
    Methods in Java
    Static and Non Static methods in Java
    Getter and Setter Methods in Java
    Major Concepts or Principles Of Object Oriented Programming In Java
    Inheritance in Java
    Polymorphism in Java
    Data Abstraction In Java
    Encapsulation in Java

    What is Object-Oriented Programming and Other Programming Paradigms

    Object-oriented programming System(OOPs) is a programming concept based on the objects that interact with each other to perform the functions. Each object can be characterized with behavior and states. An object keeps the current state and the behavior in the fields and methods. It emphasizes the DRY(Don’t Repeat Yourself) Principle.

    For instance, an object could represent an email with properties like subject, title, body, and behaviors such as attachments, sending, organizing.

    OOPs categorizes entities as software objects that have some data associated with them to perform operations upon.

    Another common programming concept is Procedural Oriented Programming(POP), which structures a program like a food recipe that provides a finite number of steps, in the form of functions or code blocks, that flow sequentially in order to get the final result.

    Almost all the programming languages follow Object Oriented Programming System including Java, let us now jump to the concepts of OOPs in java.

    Major OOPs Concepts In Java

    Data Abstraction

    Classes In Java

    A class defines the attributes and behavior of an object. For example, if you have an Employee class, it can have attributes like name, salary, and age, whereas its behavior can include functions such as deduct or increment salary or calculate bonus, etc.

    Hope you understood Classes in java, next major concept of object-oriented programming is the Objects in Java.

    Objects In Java

    Objects are the instances of classes or derived attributes and behaviors from class with actual data. Here is an example program for demonstrating classes and objects in java.
    public class Main {
    int val_1 = 22;
    int val_2 = 32;
    public static void main(String[] args) {
    // creating multiple objects for the class main
    Main obj_1 = new Main();
    Main obj_2 = new Main();
    Output for the above program
    Hope you understood Objects in java, next major concept of object oriented programming is the Methods in Java.

    Methods In Java

    Functions underclasses are known as methods. They define the behavior of a class. Here is an example for implementing methods under classes…
    import java.io.*;
    public class Main {
    static void method(String x) {
    System.out.println("Hello From "+x+ "!");
    public static void main(String[] args) {
    Output for the above program
    Hello From Atufa!
    You might have noticed that we use static or public access specifiers before the method name, let us understand static and public methods in Java.

    Static and non Static methods in Java

    In java, methods and classes are usually defined with static or public access modifiers.Defining methods or classes using static keywords makes them static, meaning they can be accessed outside the classes without creating an object for them.

    Hope you understood Methods in java well, the next major concept of object-oriented programming is the Inheritance in Java.

    Inheritance In Java

    You might have some inheritance or resemblance of behaviours in you like your parents.Just like this, you can inherit properties of one class from another.The newly inherited class is a derived or child class and the former as base or Parent class.

    Example Program  for  Inheritance implementation

    import java.io.*;
    class Main {
    // Main attribute
    protected String writer = "AL Sweigart";
    // Main method
    public void famousBook() {
    System.out.println("Automate the boring stuff with python");
    class Author extends Main {
    private int books = 22; // Author attribute
    public static void main(String[] args) {
    // Create a Author object
    Author Book = new Author();
    // Call the famousBook() method (from the Main class) on the Book object
    // Display the value of the writer attribute (from the Main class) and the
    // number of the books from the Author class
    System.out.println(Book.writer + " " + Book.books);

    The Main class is the super class, whereas the Author is the derived or child class of Main.The main method famous book can be accessed by any derived class as it is defined as public.

    Here we just needed to add another attribute and method and the rest of the attributes and methods are added to the child class by adding the extends to class name Author and defining main() method.

    The output for the above program will be
    Automate the boring stuff with python
    AL Sweigart 22
    The final keyword
    To make a class not to be inherited by any other class, we can add the final keyword to the class name.
    import java.io.*;
    final class Main {
    // Main attribute
    protected String writer = "AL Sweigart";
    // Main method
    public void famousBook() {
    System.out.println("Automate the boring stuff with python");
    class Author extends Main { // this line will cause an error
    private int books = 22;
    public static void main(String[] args) {
    Author Book = new Author();
    System.out.println(Book.writer + " " + Book.books);
    Which will give an error as
    prog.java:13: error: cannot inherit from final Main
    The different types of inheritance are single-level, multi-level and hierarchical inheritance. Hope you understood Inheritance in java well, the next major concept of object oriented programming is the Polymorphism in Java.

    Polymorphism In Java

    Polymorphism is when you use a class method in different ways or in more than one way.There are two types of polymorphism
    Run-time Polymorphism
    Compile-time Polymorphism
    Here is an example of a program to have a better understanding of Polymorphism..
    import java.io.*;
    class Shape {
    public void area() {
    System.out.println("Geometrical shapes");
    class Circle extends Shape {
    public void area() {
    class Triangle extends Shape {
    public void area() {
    class Main {
    public static void main(String[] args) {
    // create shape object
    Shape Shape = new Shape();
    Shape Circle = new Circle(); // Create a Circle object
    Shape Triangle = new Triangle(); // Create a Triangle object
    System.out.println("calling Shape method area");
    System.out.println("calling Circle method area");
    System.out.println("calling Triangle method area");

    In the above code, the class Shape is the Base class whereas Circle and Triangle are the derived or sub classes. The same method area works differently in all the classes, it returns the area of different shapes.

    The output for the above example
    calling Shape method area
    Geometrical shapes
    calling Circle method area
    calling Triangle method area

    Check out this Complete Online Java Course by FITA Academy. FITA provides a complete Java course including core java and advanced java J2EE, and SOA training, where you will be building real-time applications using Servlets, Hibernate Framework, and Spring with Aspect Oriented Programming (AOP) architecture, Struts through JDBC bundled with, placement support, and certification at an affordable price with an active placement cell,by expert software developers with 10+ years of experience in the field to make you an industry required certified java developer.

    Getter and Setter method In Java

    The attributes defined as private cannot be accessed outside the class, or the base class in case of inheritance.We will need public methods which can have access to the private attributes to retrieve or set the value of private attributes.

    Hope you understood Polymorphism in java well, the next major concept of object-oriented programming is the Encapsulation in Java.

    Encapsulation In Java

    Encapsulation in simple terms is to make the methods and attributes private or protected and give a level of security to be accessed outside the class. The keywords public, private and protected are used to give a defined level of access outside the class. Example program for Encapsulation.
    public class Encapsulation {
    /* private variables can only be accessed by public methods of same class */
    private String nickName;
    private String habit;
    private int age;
    /* getter method for accessing private variable age */
    public int get_age() {
    return age;
    /* getter method for accessing private variable nickname */
    public String get_name() {
    return nickName;
    /* getter method for accessing private variable habit */
    public String get_habit() {
    return habit;
    /* setter method for setting value for private variable age */
    public void set_age(int newAge) {
    age = newAge;
    /* setter method for setting value for private variable age */
    public void set_name(String newName) {
    nickName = newName;
    /* setter method for setting value for private variable age */
    public void set_habit(int newHabit) {
    habit = newHabit;
    Now to test this class for encapsulation, in another file encaptest.java we will have this code,
    public class encaptest {
    public static void main(String[] args) {
    Encapsulation obj = new Encapsulation();
    // setting values of the variables
    obj.set_habit("Writing content for geeks..");
    // Displaying values of the variables
    System.out.println("Writer's name: " + obj.get_name());
    System.out.println("Writer's age: " + obj.get_age());
    System.out.println("Writer's habit: " + obj.get_habit());
    * Direct access of habit is not possible due to encapsulation
    * System.out.println("Writer's habit: " + obj.habit);
    Output for the above program is
    Writer’s name: Atufa
    Writer’s age: 18
    Writer’s habit: Writing content for geeks..
    Hope you understood Encapsulation in java well, the next major concept of object oriented programming is the Data Abstraction in Java.

    Data Abstraction

    Abstraction is where in the user is kept unaware of the code that is used for implementation, for instance, when you are buying a brand new phone, it is one thing for you, although there are many individual parts in this.  Abstraction allows users to use the phone  without knowing the complexity of the parts that form the phone.

    In java you can make a class abstract by just prefixing the class name with the abstract keyword.

    An abstract method can be declared in the super class with an abstract keyword, and defined under any subclass.

    Here is an example program for abstraction

    import java.io.*;
    // An Abstract class
    abstract class Shape {
    // Abstract method (does not have a body)
    public abstract void area();
    // Regular method
    public void property() {
    System.out.println("A geometrical Shape");
    // Subclass (inherit from Shape)
    class Circle extends Shape {
    public void area() {
    // The body of area() is provided here
    System.out.println("Area of circle: pi*radius*radius");
    // Subclass (inherit from Shape)
    class Triangle extends Shape {
    public void area() {
    // The body of area() is provided here
    System.out.println("Area of triangle: half*base*height");
    class Main {
    public static void main(String[] args) {
    Circle crc = new Circle(); // Create a Circle object
    Triangle tri = new Triangle(); // Create a Triangle object
    The class shape has been defined as an abstract class, and area as an abstract method, which have been defined under the derived classes, Circle and Triangle. Output for the above program
    A geometrical Shape
    Area of circle: pi*radius*radius
    A geometrical Shape
    Area of triangle: half*base*height

    This was the end of object-oriented programming and its concepts in java with example programs. To get in-depth knowledge of core Java and advanced java, J2EE,  SOA training along with its various applications and real-time projects using Servlets, Spring with Aspect Oriented Programming (AOP) architecture, Hibernate Framework,and Struts through JDBC you can enroll in Certified Java Course in Chennai or Certified Java Course in Bangalore by FITA or a virtual class for this course,at an affordable price, bundled with real-time projects, certification, support, and career guidance assistance and an active placement cell, to make you an industry required certified java developer.

    FITA’s courses training is delivered by professional experts who have worked in the software development and testing industry for a minimum of 10+ years, and have experience of working with different software frameworks and software testing designs.

    Quick Enquiry

    Please wait while submission in progress...

    Contact Us


      93450 45466


     93450 45466


     95978 88270

    For Hiring

     93840 47472

    Corporate Training

     90036 23340

    FITA Academy Branches

    Other Locations
    FITA Academy - Velachery
    Plot No 7, 2nd floor,
    Vadivelan Nagar,
    Velachery Main Road,
    Velachery, Chennai - 600042
    Tamil Nadu

        :   93450 45466

    FITA Academy - Anna Nagar
    No 14, Block No, 338, 2nd Ave,
    Anna Nagar,
    Chennai 600 040, Tamil Nadu
    Next to Santhosh Super Market

        :   93450 45466

    FITA Academy - T Nagar
    05, 5th Floor, Challa Mall,
    T Nagar,
    Chennai 600 017, Tamil Nadu
    Opposite to Pondy Bazaar Globus

        :   93450 45466

    FITA Academy - Tambaram
    Nehru Nagar, Kadaperi,
    GST Road, West Tambaram,
    Chennai 600 045, Tamil Nadu
    Opposite to Saravana Jewellers Near MEPZ

        :   93450 45466

    FITA Academy - Thoraipakkam
    5/350, Old Mahabalipuram Road,
    Okkiyam Thoraipakkam,
    Chennai 600 097, Tamil Nadu
    Next to Cognizant Thoraipakkam Office and Opposite to Nilgris Supermarket

        :   93450 45466

    FITA Academy - Porur
    17, Trunk Rd,
    Chennai 600116, Tamil Nadu
    Above Maharashtra Bank

        :   93450 45466

    FITA Academy Marathahalli
    No 7, J J Complex,
    ITPB Road, Aswath Nagar,
    Marathahalli Post,
    Bengaluru 560037

        :   93450 45466

    FITA Academy - Saravanampatty
    First Floor, Promenade Tower,
    171/2A, Sathy Road, Saravanampatty,
    Coimbatore - 641035
    Tamil Nadu

        :   95978 88270

    FITA Academy - Singanallur
    348/1, Kamaraj Road,
    Varadharajapuram, Singanallur,
    Coimbatore - 641015
    Tamil Nadu

        :   95978 88270

    FITA Academy - Madurai
    No.2A, Sivanandha salai,
    Arapalayam Cross Road,
    Ponnagaram Colony,
    Madurai - 625016, Tamil Nadu

        :   97900 94102

  • Trending Courses

    JAVA Training In Chennai Dot Net Training In Chennai Software Testing Training In Chennai Cloud Computing Training In Chennai AngularJS Training in Chennai Big Data Hadoop Training In Chennai Android Training In Chennai iOS Training In Chennai Web Designing Course In Chennai PHP Training In Chennai Digital Marketing Course In Chennai SEO Training In Chennai

    Oracle Training In Chennai Selenium Training In Chennai Data Science Course In Chennai RPA Training In Chennai DevOps Training In Chennai C / C++ Training In Chennai UNIX Training In Chennai Placement Training In Chennai German Classes In Chennai Python Training in Chennai Artificial Intelligence Course in Chennai AWS Training in Chennai Core Java Training in Chennai Javascript Training in ChennaiHibernate Training in ChennaiHTML5 Training in ChennaiPhotoshop Classes in ChennaiMobile Testing Training in ChennaiQTP Training in ChennaiLoadRunner Training in ChennaiDrupal Training in ChennaiManual Testing Training in ChennaiSpring Training in ChennaiStruts Training in ChennaiWordPress Training in ChennaiSAS Training in ChennaiClinical SAS Training in ChennaiBlue Prism Training in ChennaiMachine Learning course in ChennaiMicrosoft Azure Training in ChennaiUiPath Training in ChennaiMicrosoft Dynamics CRM Training in ChennaiUI UX Design course in ChennaiSalesforce Training in ChennaiVMware Training in ChennaiR Training in ChennaiAutomation Anywhere Training in ChennaiTally course in ChennaiReactJS Training in ChennaiCCNA course in ChennaiEthical Hacking course in ChennaiGST Training in ChennaiIELTS Coaching in ChennaiSpoken English Classes in ChennaiSpanish Classes in ChennaiJapanese Classes in ChennaiTOEFL Coaching in ChennaiFrench Classes in ChennaiInformatica Training in ChennaiInformatica MDM Training in ChennaiBig Data Analytics courses in ChennaiHadoop Admin Training in ChennaiBlockchain Training in ChennaiIonic Training in ChennaiIoT Training in ChennaiXamarin Training In ChennaiNode JS Training In ChennaiContent Writing Course in ChennaiAdvanced Excel Training In ChennaiCorporate Training in ChennaiEmbedded Training In ChennaiLinux Training In ChennaiOracle DBA Training In ChennaiPEGA Training In ChennaiPrimavera Training In ChennaiTableau Training In ChennaiSpark Training In ChennaiGraphic Design Courses in ChennaiAppium Training In ChennaiSoft Skills Training In ChennaiJMeter Training In ChennaiPower BI Training In ChennaiSocial Media Marketing Courses In ChennaiTalend Training in ChennaiHR Courses in ChennaiGoogle Cloud Training in ChennaiSQL Training In Chennai CCNP Training in Chennai PMP Training in Chennai OET Coaching Centre in Chennai

  • Are You Located in Any of these Areas

    Adyar, Adambakkam, Anna Salai, Ambattur, Ashok Nagar, Aminjikarai, Anna Nagar, Besant Nagar, Chromepet, Choolaimedu, Guindy, Egmore, K.K. Nagar, Kodambakkam, Koyambedu, Ekkattuthangal, Kilpauk, Meenambakkam, Medavakkam, Nandanam, Nungambakkam, Madipakkam, Teynampet, Nanganallur, Navalur, Mylapore, Pallavaram, Purasaiwakkam, OMR, Porur, Pallikaranai, Poonamallee, Perambur, Saidapet, Siruseri, St.Thomas Mount, Perungudi, T.Nagar, Sholinganallur, Triplicane, Thoraipakkam, Tambaram, Vadapalani, Valasaravakkam, Villivakkam, Thiruvanmiyur, West Mambalam, Velachery and Virugambakkam.

    FITA Velachery or T Nagar or Thoraipakkam OMR or Anna Nagar or Tambaram or Porur branch is just few kilometre away from your location. If you need the best training in Chennai, driving a couple of extra kilometres is worth it!