{"id":231,"date":"2017-12-12T21:54:00","date_gmt":"2017-12-12T21:54:00","guid":{"rendered":"https:\/\/kindsonthegenius.com\/blog\/2017\/12\/12\/object-oriented-programmingoop-explained-with-java-examples-part-5\/"},"modified":"2017-12-12T21:54:00","modified_gmt":"2017-12-12T21:54:00","slug":"object-oriented-programmingoop-explained-with-java-examples-part-5","status":"publish","type":"post","link":"https:\/\/kindsonthegenius.com\/blog\/object-oriented-programmingoop-explained-with-java-examples-part-5\/","title":{"rendered":"Object Oriented Programming(OOP) Explained with Java Examples (Part 5)"},"content":{"rendered":"
\n
In this lesson, we are going to discuss the concept of polymorphism in the Java programming language.<\/p>\n
<\/a><\/div>\n

What is Polymorphism<\/b>
Polymorphism means the ability to exist in different forms. Remember that the three pillars of Object Oriented Programming is:<\/p>\n

    \n
  • Inheritance<\/li>\n
  • Abstraction<\/li>\n
  • Polymorphism<\/li>\n<\/ul>\n

    We have already discussed Inheritance and Abstraction in previous lesson. So, to be able to follow this lesson, you need a knowledge of Inheritance but you can still follow<\/p>\n

    Step 1: <\/b>Open Netbeans IDE and create an application<\/p>\n

    Step 2:<\/b> Create a class and give it a name Animal<\/i><\/p>\n

    Step 3:<\/b> Add a method to the class
    Add a method to the class called MakeSound()<\/i> defined  like this:<\/p>\n

    void MakeSound() {<\/span><\/span>
        System.out.println(“I can make a sound”);<\/span><\/span>
    } <\/span><\/span><\/p>\n

    Step 4<\/b>: Go to the function in the polymorphismLesson.java file, create a new Animal object and call its function, MakeNoise()<\/i>. The two lines you need to type into your main program would be:<\/p>\n

            Animal myPet = new Animal();   
            myPet.MakeSound(); <\/span><\/span><\/p>\n

    Step 5<\/b>: Run the program and observe that the programs runs and prints out:<\/p>\n

    I can make a sound<\/p>\n

    What happens is that the function MakeSound()<\/i> of the Animal class is called.<\/p>\n

    Step 6:<\/b> Now add three more classes to your program and name them:  Cat<\/i>, Dog<\/i> and Cow<\/i>. Add function MakeSound()<\/i> to each of them but with different implementations.<\/p>\n

    For the Cat class, the  implementation would be:
     System.out.println(“I can make a sound, meew! meew!);<\/span><\/span><\/p>\n

    For the Dog:<\/p>\n

    System.out.println(“I can make a sound, wow! wow!);<\/span><\/span><\/p>\n

    For the Cow:<\/p>\n

    System.out.println(“I can make a sound, Moo! Moo!);<\/span><\/span><\/p>\n

    Step 7:<\/b> Now go to the main program and create objects of these classes. Call the MakeNoise()<\/i> method of each class and make sure it work<\/p>\n

    Polymorphism in Action<\/b>
    Lets now see how polymorphism works in all of these<\/p>\n

    Step 8:<\/b> In your main function, create a cat object of the type Animal. Like this:<\/p>\n

    Animal myCat = new Cat(); <\/span><\/span>
    myCat.MakeNoise();<\/span><\/span><\/p>\n

    Step 9: Run this program and observe that the MakeNoise()<\/i> function of Cat is called<\/p>\n

    Step 10<\/b>: Repeat the same for Dog and Cow and observe that the right function of each of them is called<\/p>\n

    The three objects myCat<\/i>, myDog <\/i>and myCow <\/i>are of the same time Animal.  But when the MakeNoise()<\/i> is called, the correct function is called based on the class it was created from. So we can say that the MakeNoise()<\/i> function is a polymorphous function, that is same function but different behaves in different ways.<\/p>\n

    However, the concept of Polymorphism is not limited to just Polymorphous functions. In the next lesson, we would discuss another aspect of polymorphism and that is, Polymorphous Arrays.<\/p>\n

     <\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

    In this lesson, we are going to discuss the concept of polymorphism in the Java programming language. What is PolymorphismPolymorphism means the ability to exist … <\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0},"categories":[85],"tags":[],"_links":{"self":[{"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/posts\/231"}],"collection":[{"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/comments?post=231"}],"version-history":[{"count":0,"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/posts\/231\/revisions"}],"wp:attachment":[{"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/media?parent=231"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/categories?post=231"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/tags?post=231"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}