abstract factory java

1. What is abstract factory in Java?
2. What is the difference between factory and abstract factory pattern?
3. When should we use abstract factory pattern?
4. How abstract factory pattern is implemented in spring?
5. How do you use Singleton in Java?
6. What are the drawbacks for Singleton class?
7. What are abstract patterns?
8. What are factory methods in Java?
9. Why should we use factory pattern?
10. What are the consequences of applying the abstract factory pattern?
11. How do you declare an abstract class in Java?
12. What is an adapter in programming?

What is abstract factory in Java?

Abstract Factory is a creational design pattern, which solves the problem of creating entire product families without specifying their concrete classes. Abstract Factory defines an interface for creating all distinct products but leaves the actual product creation to concrete factory classes.

What is the difference between factory and abstract factory pattern?

The main difference between a “factory method” and an “abstract factory” is that the factory method is a single method, and an abstract factory is an object. The factory method is just a method, it can be overridden in a subclass, whereas the abstract factory is an object that has multiple factory methods on it.

When should we use abstract factory pattern?

3. When to Use Abstract Factory Pattern:

• The client is independent of how we create and compose the objects in the system.
• The system consists of multiple families of objects, and these families are designed to be used together.
• We need a run-time value to construct a particular dependency.

How abstract factory pattern is implemented in spring?

Applying the Abstract Factory Pattern

To apply the abstract factory pattern in the pizza store application, let us first create the products that the factories will produce. implementation classes. Next, we will write the factories that will create the products. We will start with the abstract factory.

How do you use Singleton in Java?

To design a singleton class:

1. Make constructor as private.
2. Write a static method that has return type object of this singleton class. Here, the concept of Lazy initialization is used to write this static method.

What are the drawbacks for Singleton class?

One of the main disadvantages of singletons is that they make unit testing very hard. They introduce global state to the application. The problem is that you cannot completely isolate classes dependent on singletons. When you are trying to test such a class, you inevitably test the Singleton as well.

What are abstract patterns?

Abstract Factory patterns work around a super-factory which creates other factories. This factory is also called as factory of factories. This type of design pattern comes under creational pattern as this pattern provides one of the best ways to create an object.

What are factory methods in Java?

Factory method is a creational design pattern which solves the problem of creating product objects without specifying their concrete classes. Subclasses can override this method to change the class of objects that will be created. ...

Why should we use factory pattern?

The Factory Method pattern is generally used in the following situations: A class cannot anticipate the type of objects it needs to create beforehand. A class requires its subclasses to specify the objects it creates. You want to localize the logic to instantiate a complex object.

What are the consequences of applying the abstract factory pattern?

One of the main purposes of the Abstract Factory is that it isolates the concrete classes that are generated. The actual class names of these classes are hidden in the factory and need not be known at the client level at all.

How do you declare an abstract class in Java?

Abstract class in Java

1. An abstract class must be declared with an abstract keyword.
2. It can have abstract and non-abstract methods.
3. It cannot be instantiated.
4. It can have constructors and static methods also.
5. It can have final methods which will force the subclass not to change the body of the method.

What is an adapter in programming?

Definition. An adapter allows two incompatible interfaces to work together. This is the real-world definition for an adapter. ... The adapter design pattern allows otherwise incompatible classes to work together by converting the interface of one class into an interface expected by the clients.