Java Abstraction | Object Oriented Programming |

Java Language Syllabus
https://www.gcreddy.com/2021/06/java-programming-syllabus.html

1. Introduction to Java Programming
https://gcreddy.info/introduction-to-java-programming/

2. Java Environment Setup
https://gcreddy.info/java-environment-setup/

3. Java Keywords and Identifiers
https://gcreddy.info/java-keywords-and-identifiers/

4. Java Program Structure
https://gcreddy.info/java-program-structure/

5. Java Comments
https://gcreddy.info/java-comments/

6. Java Data Types
https://gcreddy.info/java-data-types/

7. Java Variables
https://gcreddy.info/java-variables/

8. Operators in Java
https://gcreddy.info/operators-in-java/

9. Java Control Flow Statements
https://gcreddy.info/java-control-flow-statements/

10. Java Strings
https://gcreddy.info/java-strings/

11. Arrays in Java
https://gcreddy.info/arrays-in-java/

12. Java ArrayList
https://gcreddy.info/java-arraylist/

13. Java Input and Output
https://gcreddy.info/java-input-and-output/

14. Java User Defined Methods
https://gcreddy.info/java-user-defined-methods/

15. Java Built-in Methods
https://gcreddy.info/java-built-in-methods/

16. Exception Handling in Java
https://gcreddy.info/exception-handling-in-java/

17. Java Object-Oriented Programming
https://gcreddy.info/java-object-oriented-programming/

Java Abstraction is a process of hiding the implementation details and showing only functionality to the user

Two types of methods

1. Concrete Methods (The methods which are having method body)

Example:
public void add(){
Statements
.
.
}

2. Abstract Methods (the methods which are not having method body)

Example:

public abstract void add();

When we go for Abstract methods

If we know the method name but don't know the functionality then we can go for abstract methods

Java class contains 100% concrete methods

Abstract class contains one or more or all abstract methods

Class1 (having 10 methods)
All ten methods are concrete methods

It is a Java Concrete Class

Class2 (having 10 methods)
One method is abstract method and remaining nine methods are concrete methods

It is a Java Abstract Class

Class3 (having 10 methods)
All ten methods are abstract methods.

It is a Java Abstract Class
`
Example:

Class1:

public void handle() {
System.out.println("Bikes have Handle");
}
public void seat() {
System.out.println("Bikes have Seats");
}

public abstract void engine();

public abstract void wheels();

public static void main(String[] args) {
//Bikes obj = new Bikes();

}
}

Class2:

public class HeroHonda extends Bikes{
public void engine() {
System.out.println("Bikes have Engine");
}

public void wheels() {
System.out.println("Bikes have Wheels");
}

public static void main(String[] args) {
HeroHonda obj = new HeroHonda();

obj.engine();
obj.handle();
obj.seat();

}
}