How to Set Default Values in Lombok’s @Builder – A Complete Guide

1. Overview

In this tutorial we explore how to provide default values for fields when using Lombok's Builder pattern.

2. Maven Dependency

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.16.18</version>
    <scope>provided</scope>
</dependency>

3. POJO without Lombok

public class Pojo {
    private String name;
    private boolean original;
}

To make this class usable we need getters, possibly a no‑args constructor for ORM, and a builder class.

4. Adding Lombok Annotations

@Getter
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class Pojo {
    private String name;
    private boolean original;
}

The @Builder annotation alone does not assign default values, so the following tests fail.

5. Builder.Default Annotation

@Builder
public class Pojo {
    @Builder.Default
    private String name = "foo";
    @Builder.Default
    private boolean original = true;
}

This annotation supplies defaults but does not work with a generated no‑args constructor.

6. Custom Builder Class Name

@Builder(builderClassName = "PojoBuilder")
public class Pojo {
    private String name = "foo";
    private boolean original = true;
}

Specifying the builder class name avoids rename issues during refactoring.

7. Using toBuilder

@Builder(toBuilder = true)
public class Pojo {
    private String name = "foo";
    private boolean original = true;
}

Enabling toBuilder creates a builder from an existing instance, eliminating double initialization.

8. Summary

We have demonstrated several ways to give Lombok's @Builder default values, each with its own trade‑offs. Choose the approach that best fits your project.