JSON to Java POJO

Generate Java POJO classes with Jackson getters/setters or Lombok @Data from any JSON object.

Root class name

JSON Input

Java Output

What is a Java POJO?

A POJO (Plain Old Java Object) is a simple Java class that represents data — typically a JSON object or API response body. It has private fields, public getters and setters, and no business logic. POJOs are used by serialization libraries like Jackson to convert between JSON strings and Java objects (deserialization and serialization).

Writing POJOs by hand for complex JSON responses is tedious and error-prone. This tool reads any JSON object and generates the complete Java class hierarchy in seconds. Choose Jackson mode (explicit getters/setters with @JsonProperty) for maximum compatibility, or Lombok mode (@Data) to eliminate boilerplate in modern Spring Boot applications.

Jackson vs Lombok

Feature	Jackson Mode	Lombok Mode
Class annotation	@JsonIgnoreProperties	@Data + @JsonIgnoreProperties
Boilerplate	Generates getters/setters	Lombok generates at compile time
Dependency	jackson-databind	jackson-databind + lombok
Mutability	Mutable (setters)	Mutable (setters via @Data)
Best for	Standard Java projects	Modern Spring Boot apps

Lombok Maven Dependency

xml

<dependency>
  <groupId>org.projectlombok</groupId>
  <artifactId>lombok</artifactId>
  <optional>true</optional>
</dependency>

Example: Jackson Mode Output

java

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonProperty;
import java.util.List;

@JsonIgnoreProperties(ignoreUnknown = true)
public class Root {
    private Long id;
    @JsonProperty("first_name")
    private String firstName;
    private Boolean active;

    public Long getId() { return id; }
    public void setId(Long id) { this.id = id; }
    public String getFirstName() { return firstName; }
    public void setFirstName(String firstName) { this.firstName = firstName; }
    public Boolean getActive() { return active; }
    public void setActive(Boolean active) { this.active = active; }
}

Type Mapping

JSON Type	Java Type	Notes
string	String	Standard java.lang.String
integer	Long	Avoids int overflow for large IDs
float	Double	Double precision
boolean	Boolean	Boxed for null safety
null	Object	Most permissive nullable type
array	List<T>	java.util.List
object	Class	New named POJO class

Frequently Asked Questions

Lombok @Data is recommended for Spring Boot — it eliminates boilerplate and integrates perfectly with Spring's dependency injection and Jackson auto-config.

Yes. The generated classes use standard Jackson annotations which are compatible with Quarkus, Micronaut, and Jakarta EE.

Keys are converted to camelCase and a @JsonProperty annotation is added with the original key name.

It makes the class tolerant of new or unexpected fields in the JSON response, preventing deserialization errors when the API evolves.

Yes — the generated getters/setters are standard JavaBeans convention, fully compatible with MapStruct, ModelMapper, and Dozer.

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