java
Abstraction In Java With Example, abstract Class and Abstract Method
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What is Abstraction in java?
Abstraction is one of the important oops concept ,
Abstraction is defined as the process of showing the set of services and hiding the implementation.
here a real time example of abstraction is Bank ATM In ATM machine the screen showing the set of services like Cash withdraw , transfer , change Pin but in not showing the internal implementation ,this is all about abstraction.
We are achieving the abstraction by using abstract class and interface.
Using abstract class (0% to 100%)
Using interface (100%)
Before learning abstraction first we have to understand about the abstract class and abstract method .
Abstract Method
Abstract method in java ,is a method which is declare with abstract keyword and will have semicolon "; " at the end.
A abstract method is a just a signature without any implementation block inside. abstract method must be overridden in the sub class to make use of the object to invoke .
An abstract method is just a prototype for the method with the following attribute .
1) A return type
2) A name
3) A list of Parameters
4) A throws clause which is optional
Example: abstract void salary(); //This is the example of abstract method
Following is an Example of abstract method
public abstract class School//Abstract Class
{
String name;
int rollnumber;
abstract void Student ();//Abstract Method
}
Abstract Class
In java A abstract class is defined as the "Class may contain abstract method or may not contain abstract method but for the abstract classes object creation not possible ".
A class which is declare with abstract keyword is known as the abstract classes.
Important Point to Remember
Case:1 Class contain at least one abstract method
public abstract class School //Abstract Class
{
String name;
int rollnumber;
void student()
{
}
void student()
{
}
abstract void student(); //Abstract Method
}
Case:2 abstract Class does not contain abstract method
public abstract class School//Abstract Class
{
{
String name;
int rollnumber;
void student()
{
}
void student()
{
}
}
Example:1 Abstract Class Example with object Creation
//abstract parent class
abstract class Animal
{
//abstract method
public abstract void sound();
}
//Dog class extends Animal class
public class Dog extends Animal
{
public void sound()
{
System.out.println("huhuhu");
}
public static void main(String args[])
{
Animal obj = new Dog();
obj.sound();
}
}
Example -2 Inside the abstract Class declareation of main method is possible
public abstract class School //Abstract Class
{
public static void main(String args[])
{
System.out.println("Abstract main method ");
}
}
Hope !! The above Tutorial " Abstraction in java With Example " Helpful For you ...
Team,
QA acharya
This article is contributed by " Sandeep Yadav."
If you want to share your knowledge with us and would like to contribute, you can mail your article to qa.article@gmail.com.
Tags: Abstraction in java , abstraction with example in java , abstract Class and abstract method , Java abstraction , abstraction in oops , abstract class in java with example , java abstraction example
Related Post:
Abstraction is one of the important oops concept ,
Abstraction is defined as the process of showing the set of services and hiding the implementation.
here a real time example of abstraction is Bank ATM In ATM machine the screen showing the set of services like Cash withdraw , transfer , change Pin but in not showing the internal implementation ,this is all about abstraction.
We are achieving the abstraction by using abstract class and interface.
Using abstract class (0% to 100%)
Using interface (100%)
Before learning abstraction first we have to understand about the abstract class and abstract method .
Abstract Method
Abstract method in java ,is a method which is declare with abstract keyword and will have semicolon "; " at the end.
A abstract method is a just a signature without any implementation block inside. abstract method must be overridden in the sub class to make use of the object to invoke .
An abstract method is just a prototype for the method with the following attribute .
1) A return type
2) A name
3) A list of Parameters
4) A throws clause which is optional
Example: abstract void salary(); //This is the example of abstract method
- Abstract method contains only method declaration but no implementation .
- Every abstract method must ends with semicolon(;)
- We use abstract modifier to represent a method is abstract.
Following is an Example of abstract method
public abstract class School//Abstract Class
{
String name;
int rollnumber;
abstract void Student ();//Abstract Method
}
In java A abstract class is defined as the "Class may contain abstract method or may not contain abstract method but for the abstract classes object creation not possible ".
A class which is declare with abstract keyword is known as the abstract classes.
Important Point to Remember
- For the abstract classes object creation not possible.
- Abstract Class may contain abstract method or may not contain abstract method.
- Abstract class must declare with abstract modifier.
- if the class contain the abstract method then write the implementation in child classes.
- Inside the abstract class it is possible to declare the main method.
- Inside the abstract Class it is possible to declare the constructor.
- it is possible to override the abstract method to normal method.
- it is possible to override normal method to abstract method.
- Inside the abstract class it is possible to declare the variable.
- Inside the abstract class it it possible to declare the instance block and static block.
- In Child class it is possible to override the abstract method and declare user defined normal method.
Case:1 Class contain at least one abstract method
public abstract class School //Abstract Class
{
String name;
int rollnumber;
void student()
{
}
void student()
{
}
abstract void student(); //Abstract Method
}
Case:2 abstract Class does not contain abstract method
public abstract class School//Abstract Class
{
{
String name;
int rollnumber;
void student()
{
}
void student()
{
}
}
Example:1 Abstract Class Example with object Creation
//abstract parent class
abstract class Animal
{
//abstract method
public abstract void sound();
}
//Dog class extends Animal class
public class Dog extends Animal
{
public void sound()
{
System.out.println("huhuhu");
}
public static void main(String args[])
{
Animal obj = new Dog();
obj.sound();
}
}
Example -2 Inside the abstract Class declareation of main method is possible
public abstract class School //Abstract Class
{
public static void main(String args[])
{
System.out.println("Abstract main method ");
}
}
Hope !! The above Tutorial " Abstraction in java With Example " Helpful For you ...
Team,
QA acharya
This article is contributed by " Sandeep Yadav."
If you want to share your knowledge with us and would like to contribute, you can mail your article to qa.article@gmail.com.
Tags: Abstraction in java , abstraction with example in java , abstract Class and abstract method , Java abstraction , abstraction in oops , abstract class in java with example , java abstraction example
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