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Linh Nguyen
Linh Nguyen

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For the Love of God, Please Use Java Records!

Remember when creating a simple data class in Java felt like doing some sorts of heavy labor? A handful of fields, 100 lines of code (well, not 100 lines, but is pretty close), and the existential dread of knowing you'd have to do it all again, even with the help of IDE? Yeah, Java 16 finally said "our bad" and gave us Records.

If you're still writing POJOs like it's 2010, buddy, we are not the same.

We are not the same

Why Records Are Like Finding $20 in Your Old Jeans

A real life use case: You want to store a name, age, and email. In the old days, you'd write a class, add fields, generate getters, generate setters (even though you don't want them), generate equals(), generate hashCode(), generate toString(), and then realize you forgot to update equals() after adding a new field. The reviewers told you to update. You hate yourself.

Now? You write this:

public record Person(String name, int age, String email) {}
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That's it. You're done. Enough said!

Here's what you get for free (and I mean actually free, not "free trial for 30 days" free, without any credit card tomfoolery):

  • Auto-generated equals(), hashCode(), and toString() that actually work

  • Getters named like normal people talk: person.name() instead of person.getName() (because JavaBeans Specification, why not?)

  • Everything's final by default (no surprise mutations at 3 AM)

  • Can't be extended (no inheritance drama)

  • Still lets you implement interfaces (because interfaces are the true power behind Java's OOP)

One line. That's all it takes.

The Immutability Situation

So here's the deal, or a gotcha: Records make your references final. Think of it like a GPS coordinate: the location is fixed, but someone can still vandalize the building at that address.

record TreasureChest(List<String> gems) {}

var chest = new TreasureChest(new ArrayList<>(Arrays.asList("ruby")));
chest.gems().add("CURSED_GEM"); // Plot twist: nothing stops you
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The field references are locked down, but if you put a mutable collection in there? That collection is doing whatever it wants. It's giving "I didn't hear no bell" energy.

The usual suspects:

  • Collections - Lists, Sets, Maps that laugh at your immutability dreams

  • Arrays - These will betray you every single time

  • Any object with setters - Self-explanatory chaos

Your JVM is trying to do optimizations, but you keep handing it mutable state like "surprise, guess again!" The JIT compiler wants to inline constants and fold operations, but can't if it thinks your data might mutate. It's like trying to take a family photo when someone won't stop moving.

The fix? Just embrace immutability from the start. Making everything immutable is the easiest way to achieve thread safety in our chaotic world.

Where to Use Records

Use Records for:

  • DTOs that just shuttle data around

  • API requests/responses

  • Value objects (coordinates, money amounts, that kind of thing)

  • Configuration classes in Spring Boot. Seriously, it's beautiful:

@ConfigurationProperties(prefix = "app.features")
public record FeatureFlags(boolean darkMode, boolean betaAccess) {}

// Wire it up in your main class
@SpringBootApplication
@EnableConfigurationProperties(FeatureFlags.class)
public class Application { }
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Spring Boot 2.2 introduced this (needed @ConstructorBinding), then 2.6 was like "nah, we're good" and made it automatic.

TL;DR: Anything that Records can do, except for the cases like below.

DO NOT use Records for:

  • JPA entities - They need no-arg constructors, mutable fields, and proxying via inheritance. Records have none of those, so yeah, they mix and match like water and oil.

    • However, since Hibernate 6.2, you can use Records as composite IDs for your JPA entities. It's not much, but it's honest work. Records work great for JPA Projections too.

  • Mutable stuff - If you really need to mutate states, then Records cannot help you. You can, however, use "withers".

  • Custom exceptions - Records can't extend anything except java.lang.Record. And if you're using exceptions as data carriers, we have bigger problems to discuss. Why do you ask a programmer to fix the network issues? Why would you do that?

Oh, and Records are immune to those gnarly deserialization attacks by design, as everyone has to bow to its almighty canonical constructor (read: an all-args constructor). One less CVE to lose sleep over.

Data-Oriented Programming

Records aren't just "Ctrl+C, Ctrl+V prevention technology" (though they absolutely are). They're part of Java's whole vibe shift toward data-oriented programming. Combined with pattern matching, sealed classes, and switch expressions that don't make you want to cry, Records let you model your domain with immutable data and transformations.

It's like "here's some data, here's what we do with it without any ceremonies or red tapes." Honestly? It's kind of refreshing. Like finding out you can just... not have daily standup meetings.

Breaking Up With Lombok

If you've been using Lombok annotations like they're going out of style (they are), I have news. Most of them and Records go together like oil and water, or recruiters and accurate job descriptions (because why did they want someone to do the job of a whole IT department with intern salary? A.I are no excuses, you pathetic human scums!).

Most of Lombok's annotations will not work with records. You will get compiler errors or face other problems.

BUT two Lombok annotations still work:

  • @Builder - Because builder patterns are genuinely useful

  • @With - For those wither methods (and the JVM might optimize away the temporary objects, which is neat)

@Builder
@With
public record Person(String name, int age) {}

var alice = Person.builder().name("Alice").age(30).build();
var olderAlice = alice.withAge(31); // New instance, old one untouched
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@Builder helps creating an record instance easier, especially if your records have a lot of fields, and @With allows you to do some thread-safe data transformation (and pray that JVM will back you up with optimizations).

If you're stuck on Java 8 or 11, Lombok's @Value can help with immutable classes. But it's like using a flip phone in 2025: it's technically functional with limited supports, but everyone will be giving you looks (even Japanese started replacing their old "stupid" phones with more modern ones now).

Upgrade Already

Real talk: If you're still on Java 8 or 11, you're not just missing Records. You're missing pattern matching, better garbage collectors, text blocks, sealed classes, and security patches that don't require a time machine.

You're basically that person still using Windows XP because "it works fine" (spoiler alert: You will immediately be bamboozled the moment you boot up a Windows XP machine with active internet connection). Until it doesn't, and suddenly you're scrambling to fix the CVEs like trying to hold an overflowing dam with duct tapes and harsh language.

Java 17+ isn't just nice to have. It's "do you enjoy your infrastructure being held together with duct tape and prayers?" levels of necessary. It's also a new norm, so embrace it!

Most frameworks and libraries are already moving on. It is time for you, too! No excuses!

TL;DR

Records are Java admitting that sometimes you just need a dang data container, and 100 lines of boilerplate is ridiculous. They cut the nonsense, play nice with modern Java features, and work with every major framework.

The age of hand-crafted artisanal POJOs is over. And honestly? Nobody's mourning it.

Welcome to a future with less boilerplate and more time for problems that actually matter. Like arguing about tabs vs. spaces. (It's spaces, fight me.)

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