oops (inheritance&interface)
DESCRIPTION
TRANSCRIPT
![Page 1: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/1.jpg)
Main Concepts of OOP
• Encapsulation
• Inheritance
• Polymorphism
• Abstraction
![Page 2: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/2.jpg)
Encapsulation
• Encapsulation is the technique of making the fields in a class private and providing access to the fields via public methods.
• The main benefit of encapsulation is the ability to modify our implemented code without breaking the code of others who use our code.
• Encapsulation gives maintainability, flexibility and extensibility to our code.
![Page 3: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/3.jpg)
Access Specifiers in java
• public
• private
• protected
• Default
![Page 4: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/4.jpg)
Public access specifier
• A class, method, constructor, interface etc., declared public can be accessed from any other class.
• Therefore fields, methods, blocks declared inside a public class can be accessed from any class belonging to the Java Universe.
• If the public class we are trying to access is in a different package, then the public class still need to be imported.
![Page 5: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/5.jpg)
Private access specifiers
• Methods, Variables and Constructors that are declared private can only be accessed within the declared class itself.
• Private access modifier is the most restrictive access level. Class and interfaces cannot be private.
• Variables that are declared private can be accessed outside the class if public getter methods are present in the class.
• Using the private modifier is the main way that an object encapsulates itself and hide data from the outside world.
![Page 6: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/6.jpg)
Sample code for private access specifier
![Page 7: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/7.jpg)
Protected access specifier
• Variables, methods and constructors which are declared protected in a superclass can be accessed only by the subclasses in other package or any class within the package of the protected members' class.
• The protected access modifier cannot be applied to class and interfaces. Methods, fields can be declared protected, however methods and fields in a interface cannot be declared protected.
![Page 8: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/8.jpg)
Sample code for protected access specifier
![Page 9: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/9.jpg)
Default specifier
• The default specifier is used to make a class visible to all the other classes in its package but not visible to classes from other packages
![Page 10: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/10.jpg)
Inheritance
• Inheritance is a compile-time mechanism in Java that allows you to extend a class with another class
• The keyword extends is used for inheriting a Class.
• The class which extends some other class is called as derived class
• The base class is called as the super class or parent class.
![Page 11: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/11.jpg)
Types of inheritance
• Simple inheritance
• Multilevel inheritance
• Hierarchical inheritance
• Hybrid inheritance
![Page 12: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/12.jpg)
Simple inheritance
• There are only 1 base class and 1 derived class
• Syntax:
Class Parentclass
{
}
Class Dclass extendsParentclass
{
}
![Page 13: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/13.jpg)
Simple inheritance sample code and output
![Page 14: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/14.jpg)
Multilevel inheritance
• It contains derived classes which are in turn base class to another class.
class Base
{
}
class Derived1 extends Base
{
}
class Derived2 extends Derived1
{
}
![Page 15: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/15.jpg)
Multilevel inheritance sample code and output
![Page 16: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/16.jpg)
Hierarchical inheritance
• It contains one base class and more than one derived class.
class Base
{
}
class Derived1 extends Base
{
}
class Derived2 extends Base{ }
![Page 17: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/17.jpg)
Sample code and output for Hierarchical inheritance
![Page 18: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/18.jpg)
Hybrid inheritance
• It is a combination of any two or more inheritances.
![Page 19: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/19.jpg)
Sample code for hybrid inheritance
![Page 20: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/20.jpg)
Interface
• An interface in Java is similar to a class, but the body of an interface can include only abstract methods and final fields (constants).
• A class implements an interface by providing code for each method declared by the interface.
• The keyword used in interface concepts are interface and implements
![Page 21: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/21.jpg)
Syntax for interface
interface interfacename
{
method_declaration();
}
class A implements interfacename
{
method_declaration(){ }
}
![Page 22: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/22.jpg)
Interface sample code
![Page 23: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/23.jpg)
Interface sample output
![Page 24: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/24.jpg)
Any queries??
![Page 25: Oops (inheritance&interface)](https://reader033.vdocuments.site/reader033/viewer/2022051111/5538eba94a79595b7a8b48aa/html5/thumbnails/25.jpg)
Thank you