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JSON to Java Class Converter Online Free โ€” Generate POJO, Records & Lombok

Free JSON to Java class converter. Generate POJOs, Java Records (17+), and Lombok classes from JSON instantly. Supports Jackson, Gson annotations. No signup required.

About JSON to Java Conversion

Java's strong type system requires defining classes before deserializing JSON data. Manually writing Java POJOs (Plain Old Java Objects) for complex JSON APIs is tedious and error-prone. This tool analyzes your JSON and generates complete Java class definitions with proper field types, constructors, getters, and setters. It supports Lombok's @Data annotation to reduce boilerplate. Nested objects become separate classes, arrays become List<Type>, and null values are handled with nullable types. All processing happens in your browser.

Frequently Asked Questions

How do I convert JSON to Java classes?

Paste your JSON data, set a root class name, and click Convert. The tool generates Java POJO classes with proper types, fields, constructors, getters, and setters.

What is the Lombok option?

When enabled, the tool adds Lombok's @Data annotation which auto-generates getters, setters, toString, equals, and hashCode methods, significantly reducing boilerplate code.

How are arrays handled?

JSON arrays are converted to List<Type> with appropriate generic types. The tool adds the java.util.List import automatically.

Can I use the generated classes directly?

Yes. The output is valid Java code ready to use with Jackson, Gson, or any JSON library. Just copy into .java files.

Does it support Java Records?

Yes. Enable the Records option to generate Java 16+ record classes instead of traditional POJOs. Records are immutable and automatically generate equals(), hashCode(), and toString().

How are nested JSON objects converted?

Each nested JSON object becomes a separate Java class. For example, a JSON with an address object generates both a Root class and an Address class with proper type references.

Can I generate Jackson annotations?

Yes. Enable the Jackson option to add @JsonProperty annotations to each field, ensuring correct JSON serialization/deserialization in Spring Boot and other Jackson-based frameworks.

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How to Use

  1. Paste your JSON data into the input panel
  2. Set the root class name (default: Root)
  3. Toggle Lombok, Records, or Jackson annotations
  4. Copy the generated Java classes into your project

Common Use Cases

  • Creating Java POJOs from REST API responses
  • Generating model classes for Spring Boot applications
  • Building typed data models for Android apps
  • Quickly scaffolding Java classes from sample data
  • Converting API documentation JSON to Java DTOs
  • Generating domain models for microservices

Frequently Asked Questions

How do I convert JSON to Java classes?
Paste your JSON data, set a root class name, and click Convert. The tool generates Java POJO classes with proper types, fields, constructors, getters, and setters.
What is the Lombok option?
When enabled, the tool adds Lombok's @Data annotation which auto-generates getters, setters, toString, equals, and hashCode methods, significantly reducing boilerplate code.
How are arrays handled?
JSON arrays are converted to List<Type> with appropriate generic types. The tool adds the java.util.List import automatically.
Can I use the generated classes directly?
Yes. The output is valid Java code ready to use with Jackson, Gson, or any JSON library. Just copy into .java files.
Does it support Java Records?
Yes. Enable the Records option to generate Java 16+ record classes instead of traditional POJOs. Records are immutable and automatically generate equals(), hashCode(), and toString().
How are nested JSON objects converted?
Each nested JSON object becomes a separate Java class. For example, a JSON with an address object generates both a Root class and an Address class with proper type references.
Can I generate Jackson annotations?
Yes. Enable the Jackson option to add @JsonProperty annotations to each field, ensuring correct JSON serialization/deserialization in Spring Boot and other Jackson-based frameworks.