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How do we choose between using an abstract class and an interface?
Use an abstract class if you have some functionality that you want it’s subclasses to have. For instance, if you have a set of functions that you want all of the base abstract class’s subclasses to have. Use an interface if you just want a general contract on behavior/functionality.
What are abstract class and interface explain with an example?
Difference between abstract class and interface
| Abstract class | Interface |
|---|---|
| 8) A Java abstract class can have class members like private, protected, etc. | Members of a Java interface are public by default. |
| 9)Example: public abstract class Shape{ public abstract void draw(); } | Example: public interface Drawable{ void draw(); } |
What if interface and abstract class has same method?
An interface is similar to an abstract class with the exception that they do not contain any instance variables. They can be used to define a public interface of a particular type. Any class that implements an interface must implement all of the abstract interface methods, otherwise the class must be declared abstract.
What design pattern should be used to abstract?
Intent. Abstract Factory is a creational design pattern that lets you produce families of related objects without specifying their concrete classes.
Why do we use interface over abstract class?
The main advantages of interface over abstract class is to overcome the occurrence of diamond problem and achieve multiple inheritance. In java there is no solution provided for diamond problem using classes. For this reason multiple inheritance is block using classes in java.
Can we put a static method in interface?
Similar to Default Method in Interface, the static method in an interface can be defined in the interface, but cannot be overridden in Implementation Classes. To use a static method, Interface name should be instantiated with it, as it is a part of the Interface only.
Can an interface extend an abstract class?
Interface can’t provide the implementation of an abstract class. Inheritance vs Abstraction: A Java interface can be implemented using the keyword “implements” and an abstract class can be extended using the keyword “extends”.
Can we replace interface with abstract class?
Such abstract classes are similar to interfaces, except that they provide a partial implementation, leaving it to subclasses to complete the implementation. If an abstract class contains only abstract method declarations, it should be declared as an interface instead.
How are design patterns used in object oriented programming?
These Design patterns have made a huge impact in the software ecosystem and are used to date to solve common problems faced in Object-Oriented Programming. Let’s formally define the Strategy Pattern:
What do you mean by Strategy pattern in Java?
A Strategy Pattern says that “defines a family of functionality, encapsulate each one, and make them interchangeable”. The Strategy Pattern is also known as Policy. It provides a substitute to subclassing. It defines each behavior within its own class, eliminating the need for conditional statements.
What does ” program to interface ” mean in Java?
That brings us to another design principle: Program to an interface and not an implementation. What this means is that instead of using the concrete classes we use variables that are supertypes of those classes.