Java and Java EE Interview Preparations

By Navin Shet

In today’s world, for one role nearly 1000 people apply for the job and the competition is very stiff. Even the agents take the interview, so the most important thing to do is to make sure your CV is short and up to the point and has all the key skills mentioned clearly. The 2nd important thing to do is to make sure the agent forwards your CV to the employer.

This book has been written for all the Junior/Mid/Senior Java Developer, who either applying for their first job or is planning to change jobs. This book covers all the common questions covered in Interviews.

I have put all my experience into this book. I had gone through many interviews and soon realized that I need to know lot of stuff to be able to get the job. So, I started writing all the questions asked to me and my friends and soon I got the collection so big that I could write this book. By the time I could finish this book, I got several contract and permanent job offer. And there were occasions where I was made several offers and was able to negotiate the contract rate/Permanent salary as well.

Interview Process can contain a written test, Telephonic Interview or Face to Face Interview. This book prepares you for all three stages. In the new Covid world, the Face to Face is replaced with Zoom/Teams interview. It is important that you get yourself used to Zoom/Teams call and make sure camera position is correct and the lighting is good. At one instant the interviewer sent me a google docs link and asked me to write a code in Java for a sample algorithm discussed over zoom. Bu doing so interviewer could see what I am typing. So, prepare yourself well.
This book will prepare you for the Interview but expects the reader to have the basic knowledge of Java/Java EE. There are also experiences shared on how to prepare and face an interview. From my experience I found more than 90% of the interviewer will test the candidates on Core Java. So, make sure you know the first 3 chapter for sure. It is also important to know what’s in your CV. The first set of questions will be from your CV itself. And a good Interviewer can just get his/her candidate for job just by asking what’s in your CV.

This book only helps you with Interview questions. But if you to know the basics and fundamentals of Java then below are the list of books I will recommend. AS Java 17 is out, and Java is releasing a new version every 6 months. All the books and publishers are finding it difficult to keep up pace with the Java versions. But the Java basics will remain the same and any book which covers Java 8 and book is good.

• Language: English
• Publisher: Navin Shet
• Release date: Sep 19, 2021
• ISBN: 9781005025595

Book preview

Java and Java EE Interview Preparations

By Navin Shet

Copyright 2021 Navin Shet

License Notes

This e-book may not be re-sold or given away to other people. If you would like to share this book with another person, please purchase an additional copy for each recipient. If you’re reading this book and did not purchase it, or it was not purchased for your use only, then please return to Smashwords.com and purchase your own copy. Thank you for respecting the hard work of this author.

The author has made every effort in the preparation of this book to ensure the accuracy of the information. However, information in this book is sold without warranty either express or implied. The author will not be held liable for any damages caused or alleged to be caused either directly or indirectly by this book.

I would like to dedicate this book to my wife and kids, for supporting me during the good and bad times, and allowing me to go through the process of Interview. Also, would like to thank my parents and In-laws in believing in me.

All rights reserved.

PREFACE

I have 25 years of Software Development experience and have worked on almost all the Programming Language. Started With ‘C’ on UNIX and Ingress Database, and then moved on to Sybase Database.  Then Visual Basic and SQL Server, followed by some .net on C# and then SAP. And then finally started working on Java EE in 2006 and have been working on Java technology since then.

In today’s world, for one role nearly 1000 people apply for the job and the competition is very stiff. Even the agents take the interview, so the most important thing to do is to make sure your CV is short and up to the point and has all the key skills mentioned clearly. The 2nd important thing to do is to make sure the agent forwards your CV to the employer.

This book has been written for all the Junior/Mid/Senior Java Developer, who either applying for their first job or is planning to change jobs. This book covers all the common questions covered in Interviews.

I have put all my experience into this book. I had gone through many interviews and soon realized that I need to know lot of stuff to be able to get the job. So, I started writing all the questions asked to me and my friends and soon I got the collection so big that I could write this book. By the time I could finish this book, I got several contract and permanent job offer. And there were occasions where I was made several offers and was able to negotiate the contract rate/Permanent salary as well.

Interview Process can contain a written test, Telephonic Interview or Face to Face Interview. This book prepares you for all three stages. In the new Covid world, the Face to Face is replaced with Zoom/Teams interview. It is important that you get yourself used to Zoom/Teams call and make sure camera position is correct and the lighting is good. At one instant the interviewer sent me a google docs link and asked me to write a code in Java for a sample algorithm discussed over zoom. Bu doing so interviewer could see what I am typing. So, prepare yourself well.

This book will prepare you for the Interview but expects the reader to have the basic knowledge of Java/Java EE. There are also experiences shared on how to prepare and face an interview. From my experience I found more than 90% of the interviewer will test the candidates on Core Java. So, make sure you know the first 3 chapter for sure. It is also important to know what’s in your CV. The first set of questions will be from your CV itself. And a good Interviewer can just get his/her candidate for job just by asking what’s in your CV.

This book only helps you with Interview questions. But if you to know the basics and fundamentals of Java then below are the list of books I will recommend. As Java 17 is out, and Java is releasing a new version every 6 months. All the books are finding it difficult to keep up pace with the Java versions.  But the Java basics will remain the same and any book which covers Java 8 and book is good.

Table of Content

1 JAVA FUNDAMENTALS

2 JAVA MUST KNOW

3 ADVANCE JAVA

4 XML

5 Java EE

6 DESIGN PATTERN

7 UML

8 SPRING

9 DATABASE

10 UNIT TESTING

11 AGILE PROGRAMMING

12 EXERCISES

13 INTERVIEW PREPARATIONS

1 JAVA FUNDAMENTALS

Most of the questions in this chapter will be asked either in the written test, Telephonic interview or first stage interview. Most of the agents will ask questions from this chapter. So, make sure agents are happy and convinced with your answers, so that they forward your CV to the employers.

Q. What are the advantages of the object-oriented programming language (OOPL)

A. Object Oriented Programming Language is type of programming in which programmers define the data type of a data structure and the types of operations (functions) that can be applied to object. In this way an object includes both data and functions.

One of the principal advantages of OOPL techniques over procedural programming techniques is that they enable programmers to create modules that do not need to be changed when a new type of object is added. A programmer can simply create a new object that inherits many of its features from existing objects. This makes object-oriented programs easier to modify. Also, one can create real life objects like Animal, Dog, and Labrador etc.

Q. Is Java an OOPL? What are Advantages of Java Language?

A. Yes, Java is an OOPL. Advantages of Java are

Q. What are Inheritance, Encapsulation, and Polymorphism?

Aim: This question is mostly asked in written test or during telephonic interview.

A. Inheritance, Encapsulation & Polymorphism are 3 pillars of OOPL.

Polymorphism means the ability of a single variable of a given type to be used to reference objects of different types, and automatically call the method that is specific to the type of object the variable references. In a nutshell, polymorphism is a bottom-up method call. The benefit of polymorphism is that it is very easy to add new classes of derived objects without breaking the calling code that uses the polymorphic classes or interfaces.

Inheritance is the capability of a class to use the properties and methods of another class while adding its own functionality. For example, consider an employee records system. You could create a generic employee class with states and actions that are common to all employees. Then more specific classes could be defined for Permanent, commissioned and temporary employees. The generic class is known as the parent (or superclass or base class) and the specific classes as children (or subclasses or derived classes). The concept of inheritance greatly enhances the ability to reuse code as well as making design a much simpler and cleaner process.

There are two types of Inheritance

Encapsulation is the technique of making the fields in a class private and providing access to the fields via public methods. If a field is declared private, it cannot be accessed by anyone outside the class, thereby hiding the fields within the class. For this reason, encapsulation is also referred to as data hiding.

Q. What is static and dynamic binding?

A. Dynamic binding is also called as Late Binding. Dynamic Binding refers to the case where compiler is not able to resolve the call, and the binding is done at runtime only. Let's try to understand this in below example.

…

SuperClass superClass1 = new SuperClass();

SuperClass superClass2 = new SubClass();

…

superClass1.someMethod(); // SuperClass version is called

superClass2.someMethod(); // SubClass version is called

Here, we see that even though both the object references superClass1 and superClass2 are