Tired of writing hundreds of lines of boilerplate code just to store simple data? Java Records are here to simplify your life. Introduced in modern Java versions, they reduce repetitive code while providing a clean and concise way to store and transfer data. If you regularly work with data objects, you know how much time is spent writing constructors, getters, equals(), and toString(). The record in Java solves this problem, making your data models simpler, safer, and easier to maintain. This single line of code replaces hundreds of lines of error-prone boilerplate, making your data models simpler, safer, and easier to maintain.
In this guide, we’ll explore what Java Records are, how they work, their key features, and practical examples — including Java 17 record usage.
What is a Java Record?
A Java Record is a special kind of class designed primarily to hold immutable data. Its main purpose is to represent simple data carriers — objects that store data but do not change after creation.
- Preview introduced in Java 14
- Fully stable in Java 16
- Standard in Java 17 and later
When we mention a Java 17 record, we refer to the finalized and recommended version used widely today.
Basic Syntax of a Java Record
Declaring a simple data carrier for a person is straightforward:
public record Person(String name, int age) {}
You don’t need to write:
- Accessors (often called getters)
- equals() / hashCode()
- toString()
- Canonical constructors
Java generates all of these automatically, which is why the Java record class is cleaner and easier to maintain.
Traditional Class vs. Java Record
The difference in file size and complexity is immediately apparent.
Traditional Class Example
public class Person {
private final String name;
private final int age;
public Person(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() { return name; } // JavaBeans style
public int getAge() { return age; }
@Override
public String toString() { return name + ” – ” + age; }
}
Java Record Class Example
public record Person(String name, int age) {}
Crucial Note on Accessors: Unlike traditional classes that use the JavaBeans convention (getName()), a Java Record’s accessors use the component name directly. For the record above, access the data with:
person.name()
person.age()
Key Features of Java Records
| Feature | Description |
| Immutable Data | Values cannot be changed once created, ensuring data integrity. |
| Auto-generated Methods | Constructor, accessors, toString(), equals(), and hashCode() are generated automatically. |
| Simple Declaration | Just define the state components in the header. |
| Implements Interfaces | Records can implement interfaces but cannot extend other classes (they implicitly extend java.lang.Record). |
Compact Constructor for Validation
Records discourage complex logic but fully support validation during construction using the compact constructor:
public record Person(String name, int age) {
public Person {
if (age < 0) {
throw new IllegalArgumentException(“Age cannot be negative”);
}
// No explicit assignments are needed; Java handles them automatically.
}
}
Advanced Usage: Records and Pattern Matching
The true power of modern Java Records comes when you combine them with Pattern Matching (fully stable in Java 21). This allows you to inspect and destructure record data in a single clean line.
Example:
// Define a sealed hierarchy
sealed interface Shape permits Circle, Rectangle {}
public record Point(int x, int y) {}
public record Circle(Point center, int radius) implements Shape {}
public record Rectangle(int width, int height) implements Shape {}
// Use pattern matching in a method
public double getArea(Shape shape) {
return switch (shape) {
// Pattern matching deconstructs the record fields automatically!
case Circle(Point center, int r) -> Math.PI * r * r;
case Rectangle(int w, int h) -> (double) w * h;
};
}
This clean deconstruction syntax (case Circle(Point center, int r)) is a major reason developers embrace Records for complex state handling.
When Should You Use Java Records?
Use a record in Java when:
✅ You need a Data Transfer Object (DTO) ✅ Returning structured values in REST APIs or GraphQL ✅ Creating simple model classes that are immutable ✅ Implementing tuples or temporary data structures
Example: Spring Boot REST Response
public record UserResponse(Long id, String username, String email) {}
Controller Example:
@GetMapping(“/user”)
public UserResponse getUser() {
return new UserResponse(1L, “JohnDoe”, “john@example.com”);
}
Java Record Class vs. Regular Class — Quick Comparison
| Aspect | Java Record Class | Regular Class |
| Mutability | Immutable by default | Mutable (requires manual final fields) |
| Boilerplate | Minimal | High (manual constructors, accessors, etc.) |
| Inheritance | Cannot extend (java.lang.Record) | Can extend other classes |
| Accessors | Field name only (age()) | JavaBeans style (getAge()) |
| Best Use | Data holding, DTOs, simple state | Complex behaviors, mutable state, inheritance needs |
Conclusion
The Java record class is a powerful feature that simplifies code, improves readability, and makes your application state safer through enforced immutability. With Java 17 record, it has become the standard in modern Java applications — especially for APIs and microservices.
If your objects primarily carry data, switching to a record in Java is a smart, efficient choice. For more Ideas vist : Quill orbit.