Generate a Lombok @Builder POJO from JSON

The Builder Pattern with Lombok

Constructors with many parameters become unreadable quickly. Lombok's @Builder generates a fluent builder so you can construct objects field-by-field with named arguments.

Example JSON

{
  "id": 100,
  "title": "Inbox Zero",
  "description": "Reach inbox zero by Friday.",
  "priority": "high",
  "completed": false
}

Generated Java with @Data + @Builder

After running the converter with Lombok @Data enabled, manually add @Builder:

package com.example.model;

import lombok.Builder;
import lombok.Data;

@Data
@Builder
public class Task {
    private Integer id;
    private String title;
    private String description;
    private String priority;
    private Boolean completed;
}

Using the Builder

Task task = Task.builder()
    .id(100)
    .title("Inbox Zero")
    .description("Reach inbox zero by Friday.")
    .priority("high")
    .completed(false)
    .build();

Why Builders Beat Telescoping Constructors

A constructor with five parameters is hard to read at the call site:

new Task(100, "Inbox Zero", "Reach inbox zero by Friday.", "high", false);

A builder is self-documenting:

Task.builder()
    .title("Inbox Zero")
    .priority("high")
    .build();

You can omit fields, and parameter order does not matter — both major wins for readability and refactoring safety.

@Builder.Default for Defaults

If a field should default to a non-null value, mark it with @Builder.Default:

@Builder.Default
private Boolean completed = false;

Builders and Records

Records do not support Lombok @Builder because they are immutable and have a fixed canonical constructor. For records, write a static builder() method by hand or use a code-gen tool like RecordBuilder.

Builders for Deserialization

Jackson can deserialize directly into a builder if you add @JsonDeserialize(builder = Task.TaskBuilder.class) and @JsonPOJOBuilder(withPrefix = "") on the builder. This pattern is especially useful for immutable objects with many optional fields.