Book Image

The Complete Coding Interview Guide in Java

By : Anghel Leonard
Book Image

The Complete Coding Interview Guide in Java

By: Anghel Leonard

Overview of this book

Java is one of the most sought-after programming languages in the job market, but cracking the coding interview in this challenging economy might not be easy. This comprehensive guide will help you to tackle various challenges faced in a coding job interview and avoid common interview mistakes, and will ultimately guide you toward landing your job as a Java developer. This book contains two crucial elements of coding interviews - a brief section that will take you through non-technical interview questions, while the more comprehensive part covers over 200 coding interview problems along with their hands-on solutions. This book will help you to develop skills in data structures and algorithms, which technical interviewers look for in a candidate, by solving various problems based on these topics covering a wide range of concepts such as arrays, strings, maps, linked lists, sorting, and searching. You'll find out how to approach a coding interview problem in a structured way that produces faster results. Toward the final chapters, you'll learn to solve tricky questions about concurrency, functional programming, and system scalability. By the end of this book, you'll have learned how to solve Java coding problems commonly used in interviews, and will have developed the confidence to secure your Java-centric dream job.
Table of Contents (25 chapters)
1
Section 1: The Non-Technical Part of an Interview
7
Section 2: Concepts
12
Section 3: Algorithms and Data Structures
19
Section 4: Bonus – Concurrency and Functional Programming

Questions and coding challenges

In this section, we'll cover 15 questions and coding challenges related to unit testing that are very popular in interviews. Let's begin!

Coding challenge 1 – AAA

Problem: What is AAA in unit testing?

Solution: The AAA acronym stands for [A]rrange, [A]ct, [A]ssert, and it represents an approach to structuring tests to sustain clean code and readability. Today, AAA is a testing pattern that's almost a standard across the industry. The following snippet of code speaks for itself:

@Test
public void givenStreamWhenSumThenEquals6() {
  // Arrange
  Stream<Integer> theStream = Stream.of(1, 2, 3);
  // Act
  int sum = theStream.mapToInt(i -> i).sum();
  // Assert
  assertEquals(6, sum);
}

Arrange section: In this section, we prepare or set up the test. For example, in the preceding code, we prepared a stream of integers where the elements are 1, 2, and...