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Java Coding Problems

You're reading from   Java Coding Problems Become an expert Java programmer by solving over 250 brand-new, modern, real-world problems

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Product type Paperback
Published in Mar 2024
Publisher Packt
ISBN-13 9781837633944
Length 798 pages
Edition 2nd Edition
Languages
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Author (1):
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Anghel Leonard Anghel Leonard
Author Profile Icon Anghel Leonard
Anghel Leonard
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Toc

Table of Contents (16) Chapters Close

Preface 1. Text Blocks, Locales, Numbers, and Math 2. Objects, Immutability, Switch Expressions, and Pattern Matching FREE CHAPTER 3. Working with Date and Time 4. Records and Record Patterns 5. Arrays, Collections, and Data Structures 6. Java I/O: Context-Specific Deserialization Filters 7. Foreign (Function) Memory API 8. Sealed and Hidden Classes 9. Functional Style Programming – Extending APIs 10. Concurrency – Virtual Threads and Structured Concurrency 11. Concurrency ‒ Virtual Threads and Structured Concurrency: Diving Deeper 12. Garbage Collectors and Dynamic CDS Archives 13. Socket API and Simple Web Server 14. Other Books You May Enjoy
15. Index

101. Handling nulls in nested record patterns

From Chapter 2, Problem 54, Tackling the case null clause in switch, we know that starting with JDK 17 (JEP 406), we can treat a null case in switch as any other common case:

case null -> throw new IllegalArgumentException(...);

Moreover, from Problem 67, we know that, when type patterns are involved as well, a total pattern matches everything unconditionally including null values (known as an unconditional pattern). Solving this issue can be done by explicitly adding a null case (as in the previous snippet of code) or relying on JDK 19+. Starting with JDK 19, the unconditional pattern still matches null values only it will not allow the execution of that branch. The switch expressions will throw a NullPointerException without even looking at the patterns.

This statement partially works for record patterns as well. For instance, let’s consider the following records:

public interface Fruit {}
public record SeedRecord...
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