Abstract Class In Java | Java Abstract Class Tutorial | Java Tutorial For Beginners | Simplilearn

2. Agenda What is an Abstract Class? Features of Abstract Classes Rules to declare Abstract Classes Disadvantages of Abstract Classes Procedure to achieve Abstraction in Java Interface v/s Abstract Class The Syntax for Abstract Classes Interface Examples for Abstract Classes Advantages of Abstract Classes

3. What Is an Abstract Class?

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5. What Is an Abstract Class? Abstract class in Java is considered as a template of methods and variables used in a program. Abstract classes cannot be instantiated directly.

6. Features of Abstract Classes

7. Features of Abstract class Template Loose Coupling Code Reusability Abstraction Dynamic Resolution

8. Rules to Declare an Abstract Class

9. Rules to Declare an Abstract Class • The keyword “abstract” is mandatory. • Abstract classes cannot be instantiated. • An abstract class must have at least one abstract method. • An abstract class includes final methods. • An abstract class may also include non-abstract methods. • Abstract class can include constructors and static methods.

10. Procedure Procedure to Achieve Abstraction

11. Procedure Procedure to Achieve Abstraction • Abstraction is one of the fundamentals of Object-oriented programming. Abstraction can be achieved by following either of the two below mentioned procedures. • Using an Interface • Using an Abstract Class

12. The Syntax for Abstract Classes

13. Syntax of Abstract Class • Abstraction can be achieved by following the syntax mentioned below. • abstract class Simplilearn{} • abstract void Simplilearn();

14. Interface

15. Interface Interface can be defined as a boundary between the method and the class implementing it. In Java, we use interface to achieve abstraction

16. Syntax of Interface • Abstraction can be achieved by following the syntax mentioned below. • interface Simplilearn{}

17. Examples for Abstract Classes

18. I Interface V/S Abstract Class

19. Interface V/S Abstract Class Interface Abstract I Keyword: interface Keyword: abstract Subclasses extend it Subclasses implement it Only one abstract class can be extended Multiple interfaces can be implemented Does not support multiple inheritance Supports multiple inheritance

20. Advantages of Abstract Classes

21. Advantages of Abstract Class • Highly beneficial in writing shorter codes • Avoids code duplication • Enables code Reusability • Changes to Internal code implementation is done without affecting classes

22. Disadvantages of Abstract Classes

23. Disadvantages of Abstract Class • Abstraction is expensive as sometimes you need to handle cases and situation which are not necessary sometimes. • Object relational impedance mismatch in case of RDBMS • Object relational Mapping in case of Frameworks like hibernate