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Java Coding Problems
Java Coding Problems

Java Coding Problems: Improve your Java Programming skills by solving real-world coding challenges

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Java Coding Problems

Objects, Immutability, and Switch Expressions

This chapter includes 18 problems that involve objects, immutability, and switch expressions. The chapter starts with several problems about dealing with null references. It continues with problems regarding checking indexes, equals() and hashCode(), and immutability (for example, writing immutable classes and passing/returning mutable objects from immutable classes). The last part of the chapter deals with cloning objects and the JDK 12 switch expressions. By the end of this chapter, you will have a fundamental knowledge of objects and immutability. Moreover, you will know how to deal with the new switch expressions. These are valuable and non-optional bits of knowledge in any Java developer's arsenal.

Problems

Use the following problems to test your object, immutability, and switch expression programming prowess. I strongly encourage you to give each problem a try before you turn to the solutions and download the example programs:

  1. Checking null references in functional style and imperative code: Write a program that performs the null checks on the given references in a functional style and imperative code.
  2. Checking null references and throwing a customized NullPointerException error: Write a program that performs the null checks on the given references and throws NullPointerException with custom messages.
  3. Checking null references and throwing the specified exception (example, IllegalArgumentException): Write a program that performs the null checks on the given references and throws the specified exception.
  1. Checking null references and returning non-null default references...

Solutions

The following sections describe solutions to each of the preceding problems. Remember that there usually isn't a single correct way to solve a particular problem. Also, remember that the explanations shown here include only the most interesting and important details needed to solve the problems. Download the example solutions to see additional details and to experiment with the programs at https://github.com/PacktPublishing/Java-Coding-Problems.

40. Checking null references in functional style and imperative code

Independent of functional style or imperative code, checking null references is a common and recommended technique used for mitigating the occurrence of famous NullPointerException exception. This kind...

Summary

That's all folks! This chapter has introduced you to several problems involving objects, immutability, and the switch expressions. While the problems covering objects and immutability represent fundamental concepts of programming, the problems covering the switch expressions were dedicated to introducing the new JDK 12 features addressing this topic.

Download the applications from this chapter to see the results and to see additional details.

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Key benefits

  • Solve Java programming challenges and get interview-ready by using the power of modern Java 11
  • Test your Java skills using language features, algorithms, data structures, and design patterns
  • Explore areas such as web development, mobile development, and GUI programming

Description

The super-fast evolution of the JDK between versions 8 and 12 has increased the learning curve of modern Java, therefore has increased the time needed for placing developers in the Plateau of Productivity. Its new features and concepts can be adopted to solve a variety of modern-day problems. This book enables you to adopt an objective approach to common problems by explaining the correct practices and decisions with respect to complexity, performance, readability, and more. Java Coding Problems will help you complete your daily tasks and meet deadlines. You can count on the 300+ applications containing 1,000+ examples in this book to cover the common and fundamental areas of interest: strings, numbers, arrays, collections, data structures, date and time, immutability, type inference, Optional, Java I/O, Java Reflection, functional programming, concurrency and the HTTP Client API. Put your skills on steroids with problems that have been carefully crafted to highlight and cover the core knowledge that is accessed in daily work. In other words (no matter if your task is easy, medium or complex) having this knowledge under your tool belt is a must, not an option. By the end of this book, you will have gained a strong understanding of Java concepts and have the confidence to develop and choose the right solutions to your problems.

Who is this book for?

If you are a Java developer who wants to level-up by solving real-world problems, then this book is for you. Working knowledge of Java is required to get the most out of this book.

What you will learn

  • Adopt the latest JDK 11 and JDK 12 features in your applications
  • Solve cutting-edge problems relating to collections and data structures
  • Get to grips with functional-style programming using lambdas
  • Perform asynchronous communication and parallel data processing
  • Solve strings and number problems using the latest Java APIs
  • Become familiar with different aspects of object immutability in Java
  • Implement the correct practices and clean code techniques

Product Details

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Publication date, Length, Edition, Language, ISBN-13
Publication date : Sep 20, 2019
Length: 816 pages
Edition : 1st
Language : English
ISBN-13 : 9781789800500
Category :
Languages :

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Product feature icon AI Assistant (beta) to help accelerate your learning

Product Details

Publication date : Sep 20, 2019
Length: 816 pages
Edition : 1st
Language : English
ISBN-13 : 9781789800500
Category :
Languages :

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Table of Contents

14 Chapters
Strings, Numbers, and Math Chevron down icon Chevron up icon
Objects, Immutability, and Switch Expressions Chevron down icon Chevron up icon
Working with Date and Time Chevron down icon Chevron up icon
Type Inference Chevron down icon Chevron up icon
Arrays, Collections, and Data Structures Chevron down icon Chevron up icon
Java I/O Paths, Files, Buffers, Scanning, and Formatting Chevron down icon Chevron up icon
Java Reflection Classes, Interfaces, Constructors, Methods, and Fields Chevron down icon Chevron up icon
Functional Style Programming - Fundamentals and Design Patterns Chevron down icon Chevron up icon
Functional Style Programming - a Deep Dive Chevron down icon Chevron up icon
Concurrency - Thread Pools, Callables, and Synchronizers Chevron down icon Chevron up icon
Concurrency - Deep Dive Chevron down icon Chevron up icon
Optional Chevron down icon Chevron up icon
The HTTP Client and WebSocket APIs Chevron down icon Chevron up icon
Other Books You May Enjoy Chevron down icon Chevron up icon

Customer reviews

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Full star icon Full star icon Full star icon Full star icon Half star icon 4.7
(9 Ratings)
5 star 77.8%
4 star 11.1%
3 star 11.1%
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Cristian Oct 01, 2019
Full star icon Full star icon Full star icon Full star icon Full star icon 5
"Java Coding Problems" contains an engaging set of programming problems, complete with jdk8-jdk12 solutions. It makes catching up with core java API updates quick, intuitive and pleasurable.Full disclosure: I was a technical reviewer for this book.
Amazon Verified review Amazon
Prasanti Nov 03, 2020
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Excellent book for those looking for coding techniques with latest java version.
Amazon Verified review Amazon
ALEXANDRE Oct 04, 2022
Full star icon Full star icon Full star icon Full star icon Full star icon 5
The book is fantastic but of course, you need to know if it is the right level for you. I mean, you need the prerequisite knowledge to read and understand it.I really recommend those who are willing to be prepared for technical interview questions coded by Java 8+.
Amazon Verified review Amazon
Ivan de Oliveira Costa Junior Dec 13, 2021
Full star icon Full star icon Full star icon Full star icon Full star icon 5
The author brings to the table a lot of content that is deeper than the other book "Complete Coding Interview" so you buy this if you need to learn things in a more profound way. I've found it very easy to read and useful as well, however isn't required for ones wishing to be prepared for an interview.
Amazon Verified review Amazon
Yogan Naidoo Oct 02, 2020
Full star icon Full star icon Full star icon Full star icon Full star icon 5
As an intermediate Java developer I gained a lot from this book. I will definitely use it as a reference going forward. The sample code was good and easy to try. I especially enjoyed the chapters on Functional Programming. My feeling is that you pick the chapters that will benefit you the most and start with those.
Amazon Verified review Amazon
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