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Java Coding Problems - Second Edition

You're reading from  Java Coding Problems - Second Edition

Product type Book
Published in Mar 2024
Publisher Packt
ISBN-13 9781837633944
Pages 798 pages
Edition 2nd Edition
Languages
Author (1):
Anghel Leonard Anghel Leonard
Profile icon Anghel Leonard

Table of Contents (16) Chapters

Preface 1. Text Blocks, Locales, Numbers, and Math 2. Objects, Immutability, Switch Expressions, and Pattern Matching 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

95. Invoking the canonical constructor via reflection

It is not a daily task to invoke the canonical constructor of a Java record via reflection. However, this can be accomplished quite easily starting with JDK 16, which provides in java.lang.Class the RecordComponent[] getRecordComponents() method. As its name and signature suggest, this method returns an array of java.lang.reflect.RecordComponent representing the components of the current Java record.

Having this array of components, we can call the well-known getDeclaredConstructor() method to identify the constructor that gets as arguments exactly this array of components. And that is the canonical constructor.

The code that puts these statements into practice is provided by the Java documentation itself, so there is no need to reinvent it. Here it is:

// this method is from the official documentation of JDK
// https://docs.oracle.com/en/java/javase/19/docs/api/
// java.base/java/lang/Class.html#getRecordComponents...
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