Design Pattern - Creational

Question 1

Abstract Factory

Answer 1

Works around a super-factory which creates other factories. This factory is also called a factory of factories. It is an interface that is responsible for creating a factory of related objects without explicitly specifying their classes. Each generated factory can give the objects as per the Factory pattern.

Question 2

Builder

Answer 2

Builds a complex object using simple objects and using a step-by-step approach. This builder is independent of other objects.

Question 3

Factory Method

Answer 3

One of the most used design patterns in Java. Create objects without exposing the creation logic to the client and refer to the newly created object using a common interface.

Question 4

Object Pool

Answer 4

Avoid expensive acquisition and release of resources by recycling objects that are no longer in use.

Question 5

Prototype

Answer 5

Refers to creating duplicate objects while keeping performance in mind. Involves implementing a prototype interface which tells to create a clone of the current object. This pattern is used when the creation of an object directly is costly. For example, an object is to be created after a costly database operation. We can cache the object, returns its clone on the next request, and update the database as and when needed thus reducing database calls.

Question 6

Singleton

Answer 6

A single class responsible for creating an object while making sure that only a single object gets created. This class provides a way to access its only object which can be accessed directly without the need to instantiate the object of the class.