Interview Questions.

Interview Questions and Answers For Design Patterns


Interview Questions and Answers For Design Patterns

Q1. What is Design Pattern?

Ans: Design Pattern In software is a quality practice a wellknown, reusable approach to a commonplace trouble faced by using software program builders within a given context in software program layout.

Design styles are high-quality practices that programmer can use to solve not unusual issues whilst designing a gadget or software.

Q2. What are the sorts of Design Patterns?

Ans: Creational Patterns

Structural Patterns

Behavioral Patterns

Q3. What is supposed through Gang of Four GOF?

Ans: The four authors Erich Gamma, Richard Helm, Ralph Johnson and John Vlissides These authors are collectively referred to as Gang of Four GOF.

These initiated the idea of Design Pattern in Software improvement In 1994 & posted a book titled Design Patterns - Elements of Reusable Object-Oriented Software

Q4. What are J2EE Patterns?

Ans: J2EE Patterns concerned with the presentation tier.

Q5. What is Factory sample?

Ans: Factory pattern is one of the most used layout styles in Java. ... In Factory sample, we create object with out exposing the introduction common sense to the customer and seek advice from newly created object the use of a common interface.

Q6. Can we create a identical to a singleton item?

Ans: Yes

Q7. How to create Singleton magnificence in java?

Ans: There are two steps on this system.

First, make the constructor non-public in order that new operator can not be used to instantiate the elegance.

Return an item of the item if now not null in any other case create the object and go back the same via a method.

Q8.What is the advantage of Factory sample?

Ans: Factory pattern encapsulates the implementation info and underlying implementation may be changed without any effect on caller api.

Q9. What is Singleton pattern?

Ans: In software engineering, the singleton sample is a software layout sample that restricts the instantiation of a category to 1 item. This is useful while exactly one object is wanted to coordinate moves throughout the gadget.

Q10. What is Abstract Factory sample?

Ans: Abstract manufacturing unit pattern is also referred to as manufacturing facility of factories.The abstract manufacturing facility pattern gives a way to encapsulate a set of individual factories that have a not unusual theme without specifying their concrete classes.

Q11. How to prevent cloning of a singleton item?

Ans: By Throwing exception in the body of clone method.