@RequiredArgsConstructor annotation in Spring Boot

The @RequiredArgsConstructor annotation is a feature of Lombok, a Java library that helps reduce boilerplate code.

When you use @RequiredArgsConstructor on a class, Lombok generates a constructor for all fields that are marked as final or are marked with @NonNull.

This is particularly useful for creating immutable objects or for dependency injection.

Here’s a simple example of how it works:

import lombok.RequiredArgsConstructor;

@RequiredArgsConstructor
public class MyTestClass {
    private final String requiredField;
    private final int anotherRequiredField;
    private String optionalField;
}

In this example, Lombok will generate a constructor like this:

public MyTestClass(String requiredField, int anotherRequiredField) {
    this.requiredField = requiredField;
    this.anotherRequiredField = anotherRequiredField;
}

The optionalField is not included in the constructor because it's neither final nor marked with @NonNull.

To use Lombok, you need to include it as a dependency in your project and have the Lombok plugin installed in your IDE. For Maven, you would add it to your pom.xml like this:

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.34</version>
    <scope>provided</scope>
</dependency>

Lombok can make your code cleaner and easier to maintain by reducing the need for boilerplate code.