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JSON to Java POJO Generator - Convert JSON to Java Classes Online

Convert JSON to Java POJOs instantly — with nested classes, List arrays, Lombok & Jackson annotations, and one-click code download.

// Java POJO classes will appear here

What is a JSON to Java POJO Generator?

A JSON to Java POJO generator is a free online tool that reads a JSON object — such as an API response, configuration file, or database record — and automatically generates matching Java classes (Plain Old Java Objects). Instead of writing fields, getters, setters, and nested classes by hand, you paste your JSON, click generate, and get clean, compilable Java code ready for Spring Boot, Jackson, Android, or any JVM project.

Why Convert JSON to Java POJOs?

Java applications constantly serialize and deserialize JSON. Writing POJOs for large, nested payloads by hand is slow and error-prone. This generator infers the exact shape of your data — including nested objects, typed List collections, numbers, and booleans — so you get accurate, maintainable Java models every time.

  • Generate Java classes from JSON instantly
  • Create nested classes for nested JSON objects
  • Map arrays to typed List<T> collections
  • Add Lombok @Data or full getters & setters
  • Add Jackson @JsonProperty for non-Java keys
  • Copy or download the code as a .java file

Common JSON to Java POJO Use Cases

🌱

Spring Boot APIs

Generate request and response models for REST controllers.

🔄

Jackson Mapping

Produce POJOs that deserialize cleanly with ObjectMapper.

📱

Android Apps

Build model classes for Retrofit and Gson networking.

✨

Lombok Models

Generate compact POJOs annotated with @Data in one click.

🗄️

Data Models

Bootstrap DTOs and entity-style classes from sample data.

📨

Kafka & Messaging

Create message payload classes for event-driven systems.

How to Convert JSON to a Java POJO

  1. Paste your JSON into the input box (or upload a .json file).
  2. Set the package name and root class name.
  3. Toggle Lombok, primitive types, and Jackson annotations.
  4. Click Generate to create the Java classes.
  5. Copy the code or download it as a .java file.

Everything You Should Know About Java POJOs & Lombok

A POJO (Plain Old Java Object) is a simple Java class with private fields and public accessors, free of framework-specific requirements. POJOs are the backbone of data transfer objects (DTOs), API models, and entities across the Java ecosystem.

  • Nested classes: nested JSON objects become separate Java classes referenced by type, keeping models clean and reusable.
  • Collections: JSON arrays map to List<String>, List<Integer>, or List<User> for arrays of objects.
  • Lombok: annotations like @Data, @NoArgsConstructor, and @AllArgsConstructor remove boilerplate getters, setters, and constructors.
  • Jackson: @JsonProperty maps JSON keys like user_name to Java fields like userName during serialization.
  • Primitive vs wrapper types: choose int/double for performance or Integer/Double for nullable fields.

This generator applies all of these conventions automatically, so the output matches how an experienced Java developer would model the same data.

JSON to Java POJO for Developers

This generator is designed for:

  • Spring Boot & Spring MVC developers
  • Android developers using Retrofit & Gson
  • Backend engineers building REST & GraphQL APIs
  • Microservices & Kafka developers
  • Jakarta EE & Quarkus developers
  • QA & automation engineers
  • Students learning Java and JSON mapping

🎥 Video Guide

❓ FAQs

What is a JSON to Java POJO generator?

A JSON to Java POJO generator is a tool that reads a JSON object and automatically creates matching Java classes (Plain Old Java Objects), including fields, nested classes, and typed collections, so you don't have to write boilerplate by hand.

How do I convert JSON to a Java POJO?

Paste your JSON into the input box, set the package and root class name, choose your options, and click Generate. The tool infers each field's type and produces ready-to-use Java classes you can copy or download.

Is this JSON to Java POJO generator free?

Yes. The generator is completely free with no limits, sign-up, or installation required.

Does it support nested classes?

Yes. Nested JSON objects are turned into separate Java classes in the same file and referenced by type, giving you clean, reusable POJOs for deeply nested data.

How are JSON arrays converted?

Arrays become typed collections using java.util.List, such as List<String> or List<Post>. Arrays of objects are merged into a single class and typed as List<ClassName>.

Does this generator support Lombok?

Yes. Enable Lombok to annotate classes with @Data, @NoArgsConstructor, and @AllArgsConstructor instead of generating explicit getters and setters, keeping your POJOs compact.

Can I add Jackson annotations?

Yes. When a JSON key cannot be a valid Java field name (for example snake_case or names with spaces), the tool adds a Jackson @JsonProperty annotation so deserialization still maps correctly.

Can I download the generated Java code?

Yes. You can copy the generated classes to your clipboard or download them as a .java file ready to drop into your project.

Does it generate getters and setters?

Yes. When Lombok is turned off, the generator produces standard getters and setters (and idiomatic isX() getters for boolean fields) for every field.

Can I choose primitive or wrapper types?

Yes. You can generate primitive types like int, double, and boolean, or switch to wrapper types like Integer, Double, and Boolean for nullable fields.

Is my JSON data secure?

Yes. All conversion happens entirely inside your browser. Your JSON is never uploaded to a server or stored anywhere, so it stays completely private.

How are numbers typed?

Whole numbers become int (or long when the value is too large for int) and decimals become double. You can switch to wrapper types if you prefer Integer, Long, or Double.

What happens with null values?

Fields that only ever contain null are typed as Object, since the JSON does not provide enough information to infer a more specific type.

Does this work with REST API responses?

Absolutely. Paste a sample response from any REST API and instantly get Java POJOs for Spring Boot, Jackson, Retrofit, or Android networking code.

Which browsers support this tool?

The JSON to Java POJO generator works on Chrome, Firefox, Safari, Edge, and all modern browsers with JavaScript support.