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

How many times have you
written..

One of these good-old
Java Classes

One of these good-old
Java Classes
Fields

One of these good-old
Java Classes
Fields
Constructor

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

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

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

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

Just to store a values pair
(name, age)

And how many times did you
wish it did end?

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

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

More code = More places for bugs

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

Code.. Code.. Code..
Demo

All is good.. right?

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

Far from an ideal solution

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?

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?

More show me
Demo

Record-ify the Person Class
Demo

Getters
• record.fieldName( )
Demo

Custom Logic
• record.methodName( )
Demo

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

Strip the constructor down
• public record {…}
Demo

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

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

Making Life Simple
Java
Developers

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

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

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

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