The document discusses Java records, which were introduced in Java 14 to provide a simpler way of creating classes that mainly store and retrieve data. Records reduce boilerplate code by automatically generating common methods like constructors, getters, equals, hashCode and toString. They model data as data rather than objects, making the code easier to read and less error-prone. The document demonstrates how to define and use records, customize their behavior, and convert an existing class to a record for simplification. It argues that records are well-suited for data transfer objects and other classes without significant business logic.

1. Coming Clean on Records
A glance at what’s coming your way
Albin Hasani
Twitter: @albihasani94

2. How many times have you
written..

3. One of these good-old
Java Classes

4. One of these good-old
Java Classes
Fields

5. One of these good-old
Java Classes
Fields
Constructor

6. One of these good-old
Java Classes
Fields
Constructor
Getters and setters

7. One of these good-old
Java Classes
Fields
Constructor
Getters and setters
equals

8. One of these good-old
Java Classes
Fields
Constructor
Getters and setters
equals
hashCode

9. One of these good-old
Java Classes
Fields
Constructor
Getters and setters
equals
hashCode
toString

10. Just to store a values pair
(name, age)

11. And how many times did you
wish it did end?

12. – Cicero
“When in doubt, run to the IDE.”
Demo

13. Some Inconveniences
• Not perfect for classes that are just wrappers for some data
• Lots of boilerplate: constructors, accessors, equals,
hashCode, toString
• No fun to write => Delegate to the IDE
• Reading does not feel like reading developer’s intent

14. More code = More places for bugs

15. The Pair Awakens
• Part of the javafx.util package
• Pair<K, V> pair = new Pair<>(K key, V value)
• K getKey( ), V getValue( )
• It gets you a standard implementation of equals,
hashCode, and toString

16. Code.. Code.. Code..
Demo

17. All is good.. right?

18. Well, not exactly
• The notion of type names is lost, only key-value pair
gets printed out
• JavaFX has been removed from JDK 11
• Its module/jar has to be included on each compilation
and runtime
• Overhead saved from the Person class => traded with
some overhead in configuration

19. Far from an ideal solution

20. Rise of the Record
• record Person (String name, int age) { }
• Transparent holders for shallowly immutable data
• Modeling data as data
• The data, the whole data, and nothing but the data
What are records?

21. Living with records
• Boilerplate reduction, obviously
• Good semantics => easier to read, less error prone
• Defaults for constructor, getters, equals, hashCode,
and toString
• Extension by methods, custom constructor
What do they offer?

22. More show me
Demo

23. Record-ify the Person Class
Demo

24. Getters
• record.fieldName( )
Demo

25. Custom Logic
• record.methodName( )
Demo

26. Custom Constructor
• public record(String name, int age) {…}
Demo

27. Strip the constructor down
• public record {…}
Demo

28. Stream Case Study
• Method computed for every comparison
yearsTo100( )
Demo

29. Record: Performance Gain
• Method computed for every comparison
yearsTo100( )
Demo

30. Making Life Simple
Java
Developers

31. Records
• Convenient data stores
• Ideal for DTOs and classes without much business logic
• Far less boilerplate
• Lightweight constructor syntax
• Readability over lines of code

32. – Obi-Wan Kenobi
“Use the record, Luke.”

33. Pay Java records a visit!
115 W CHIPPEWA ST - DOWNTOWN BUFFALO, NY (corner of Delaware)

34. If you have any questions
Please reach out directly after the talk in person
or leave me a message @albihasani94 on twitter
Albin Hasani
Twitter: @albihasani94