Slide 1
UNIT- ICHAPTER IN BOOK- 8part- II-K. IndhuSYLLABUS COVERED
HEREINHERITANCEK. INDHUGoalsOrder of Constructors Calling in
InheritanceMethod OverridingExample for Method OverridingExample
with super()Method OverloadingDynamic Dispatch IntroductionExample
for Dynamic DispatchAbstract Class in JavaDynamic Dispatch thru
Abstract ClassUses of Abstract ClassUsing Final to prevent
Overriding (Method)Using Final to prevent Inheriting (Class)Object
Class & its methods in Java
K. INDHUOrder of constructorsK. INDHU
Order of constructorsK. INDHU
Method overridingDEFINITION->In a class hierarchy, when a
method in a subclass has the same name and type signature as a
method in its super-class, then the method in the subclass is said
to override the method in the super-class.
When an overridden method is called from a subclass, it will
always refer to the version of that method defined by the
subclass.
The version of the method defined by the super-class will be
hidden.K. INDHUexampleK. INDHU
exampleK. INDHU
Example with super()K. INDHU
Method overloadingK. INDHU
Method overloadingK. INDHU
Dynamic dispatch introMethod overriding forms the basis for one
of Javas most powerful concepts: dynamic method dispatch.
Dynamic method dispatch is the mechanism by which a call to an
overridden method is resolved at run time, rather than compile
time.
Thru Dynamic Dispatch, Java implements run-time polymorphism.K.
INDHUDynamic dispatch introA super-class reference variable can
refer to a subclass object.
Java uses this fact to resolve calls to overridden methods at
run time.
Therefore, if a super-class contains a method that is overridden
by a subclass-then when different types of objects of sub-classes
are referred to through a super-class reference variable,different
versions of the method are executed at run time.K. INDHUDynamic
dispatch (ex)K. INDHU
Dynamic dispatch (ex)K. INDHU
Dynamic dispatch (ex)K. INDHU
Dynamic dispatch (ex)K. INDHU
Abstract class in javaDEFINITION FOR ABSTRACT CLASS->A
class->that is declared as abstract,which needs to be extended
and its abstract method implemented and,that cannot be
instantiated, -> is called as Abstract Class.
DEFINITION FOR ABSTRACT METHOD->A method that is declared as
abstract and does not have implementation is known as abstract
method.
Abstract Class can have both abstract and concrete methods.One
of the ways to achieve Abstraction in Java.
K. INDHUAbstract class in javaK. INDHU
Dynamic dispatch thru Abstract classK. INDHU
Dynamic dispatch thru Abstract classK. INDHU
Uses of abstract class(1) It can provide basic functionality,
but in order for that functionality to be used, one or more other
classes must derive from the abstract class.
(2) Abstract Class is one of the ways to achieve abstraction
(OOPS Principle).
(3) One of the major benefits of abstract classes is that you
can reuse code without having to retype it. That has a plethora of
benefits, such as reducing bugs and making coding faster.K.
INDHUUsing finalto Prevent OverridingK. INDHU
Using finalto Prevent inheritingK. INDHU
Object class in javaThere is one special class, Object, defined
by Java.
All other classes are subclasses of Object. That is, Object is a
super-class of all other classes.
This means that a reference variable of type Object can refer to
an object of any other class.
Also, since arrays are implemented as classes, a variable of
type Object can also refer to any array.K. INDHUMethods in object
classK. INDHU
So far we studiedInheritanceK. INDHUHAPPY LEARNING!!!
