• What is a Record?
• Characteristics of Records
• Why Use Records?
• Conclusion

Java continually evolves to provide developers with a better programming experience. The introduction of 'Record' as a preview feature in Java 14 exemplifies this effort.

This post will explore the concept of Java's 'Record' and the reasons for its usage.

What is a Record?

In Java, a 'Record' is a new type that allows for the concise definition of immutable objects that only contain data.

In traditional Java, defining a data-only class required a lot of boilerplate code, including constructors, getters, equals(), hashCode(), toString(), and various other methods.

Records alleviate this inconvenience by enabling data representation with a more concise syntax.

public record ItemResponseDto (
    @Schema(description = "Item ID", example = "1")
    Long itemId,

    @Schema(description = "User information")
    UserResponseDto user,

    @Schema(description = "Item like count")
    int itemLikeCount
) {
  public ItemResponseDto(User user, Item item) {
    this(
      item.getId(),
      new UserResponseDto(user),
      item.getLikeCount()
    );
  }
}

Characteristics of Records

1. Immutability: All fields in a Record are immutable. Once created, their values cannot be changed.
2. Automatic Provision of Standard Methods: Methods such as equals(), hashCode(), and toString() are automatically provided.
3. Restricted Inheritance: Records cannot extend other classes, nor can they be extended.

Why Use Records?

1. Conciseness: Reduces boilerplate code when defining data-only classes like DTOs.
2. Clear Intent: Using Records clearly indicates that the class is meant for data only.
3. Guaranteed Immutability: Ensures data immutability, minimizing bugs and enhancing code stability.

Conclusion

Java Records simplify the definition of data-only classes while ensuring code stability and clarity.

When defining objects that represent data and require reduced boilerplate code, consider using 'Record'.