JSON to Java Class Generator Online

What Is a JSON to Java Class Generator?

A JSON to Java class generator analyzes JSON data and produces Java POJO (Plain Old Java Object) class definitions with typed fields that match the JSON structure. Java's strong type system requires explicit class definitions to deserialize JSON using libraries like Jackson, Gson, or the built-in javax.json API. Writing these classes manually for complex API responses with nested objects and arrays is error-prone and time-consuming.

This tool examines each JSON property, maps it to the appropriate Java type (String, int, double, boolean, List, or nested class), generates private fields with standard Java naming conventions, and creates separate class files for nested object types. The result is ready-to-use Java code that works with Jackson's ObjectMapper or Gson's fromJson methods. All generation happens locally in your browser with 100% client-side processing, keeping your API data private.

How to Generate Java Classes from JSON

1. Paste your JSON data into the input panel. REST API responses, database query results, or any valid JSON object is accepted.
2. Click Convert to analyze the JSON structure and generate Java POJO classes with properly typed private fields.
3. Review the generated classes with correct Java types, nested class definitions, and List types for array properties.
4. Copy the Java code and paste into your .java files. Add getters/setters or use Lombok's @Data annotation for a complete implementation.

Why Use PinusX JSON to Java Generator?

Java developers building Spring Boot APIs, Android applications, and enterprise services constantly need POJO definitions that match JSON API contracts. PinusX generates accurate Java classes instantly with 100% client-side processing — your API responses from Spring services, third-party integrations, and internal microservices never leave your browser. This matters when working with production payloads containing sensitive employee data, financial transactions, or healthcare records that must not be exposed to external services.

Frequently Asked Questions

What Java types are generated?

JSON strings map to Java 'String', integers to 'int', decimal numbers to 'double', booleans to 'boolean', null to 'Object', arrays to 'List<T>', and nested objects to separate class definitions. The type mapping follows standard Java conventions.

Are getters and setters included?

The generator produces classes with private fields. You can add getters and setters manually, use your IDE's code generation, or annotate the class with Lombok's @Data annotation. This approach keeps the generated code minimal and flexible.

Does it work with Jackson?

Yes. The generated POJOs work directly with Jackson's ObjectMapper.readValue() for JSON deserialization. Field names match JSON keys, and nested objects are properly typed for recursive deserialization by Jackson.

How are nested objects handled?

Nested JSON objects generate separate Java classes with names derived from the parent class and field name. For example, a 'department' field containing an object generates a 'RootDepartment' class with its own typed fields.

Is my JSON data safe?

Yes. All JSON to Java class generation runs locally in your browser. No API data, employee records, or business information is sent to any server. Your data stays entirely on your machine during the generation process.

Your data never leaves your browser. 100% client-side processing.