Convert JSON to Java online, free. JSON is the dominant data-interchange format for web APIs and config. Java POJOs/records model structured data for the JVM. JSON to Java conversion parses your JSON against the ECMA-404 / RFC 8259 grammar (https://www.rfc-editor.org/rfc/rfc8259), builds an in-memory model of its keys, nested objects and arrays, then emits ready-to-use Java types as POJOs with Jackson annotations following the Java Language Specification conventions. Processing runs in your browser in JavaScript with no upload or server round-trip — no size limit beyond your device's memory, so multi-megabyte documents convert in milliseconds and sensitive payloads never leave your machine. Typical uses include Spring/Jackson data binding, Android models and enterprise services.
It maps the full structure of your JSON onto idiomatic Java types, following the Java Language Specification conventions. 100% free, no registration, and complete privacy — everything runs locally in your browser, so your data never touches a server.
Paste JSON and generate Java types from Java immediately. Conversion runs client-side, so there is no upload wait and large documents stay fast.
Nested JSON objects, tables and arrays are mapped faithfully onto Java, including nested types and optional fields.
Your JSON never leaves your device — everything is processed locally in JavaScript, with nothing logged or stored.
Unlimited conversions with no account, no quotas, and no watermark. Works on desktop and mobile.
A JSON document and its Java equivalent:
JSON input:
{
"title": "Dune",
"pages": 412,
"available": true
}Output:
public record Book(
String title,
int pages,
boolean available
) {}Paste your JSON into the editor and press "Convert to Java". The tool parses it against the ECMA-404 / RFC 8259 grammar, then generates Java types following Java Language Specification conventions — instantly and entirely in your browser. You can validate or format the JSON first to be sure it is clean.
JSON already uses objects, arrays and typed scalars, so mapping to Java is close to one-to-one: objects become types or structs, arrays become lists, and numbers, booleans and null keep their types.
Optional or nullable members in the generated Java are inferred from keys missing in some records of your JSON, following Java Language Specification. Include the optional fields in your sample so they are typed correctly.
JSON (JavaScript Object Notation) (JSON) — JSON is the dominant data-interchange format for web APIs and config. Java classes (Java) — Java POJOs/records model structured data for the JVM. This converter maps the structure of your JSON onto Java so you can use it for Spring/Jackson data binding.
Yes. Invalid JSON is flagged with a clear error before anything is converted. Common JSON problems to check are matched braces and brackets, double-quoted keys, and no trailing commas. Starting from clean input keeps the generated Java accurate.
Yes. The entire JSON-to-Java conversion runs locally in your browser in JavaScript — your JSON is never uploaded, logged or stored. That matters when the data is something like REST/GraphQL API payloads, which should not leave your machine.
The generated Java is ready for Spring/Jackson data binding, Android models and enterprise services. Copy or download it and drop it straight into your codebase.
This tool is designed to help you quickly convert JSON to Java classes. Simply paste your JSON structure on the left, and the tool will automatically generate the corresponding Java classes on the right. You can then copy the Java classes and use them directly in your Java project. While the tool makes intelligent assumptions for the conversion, we recommend reviewing the output to ensure everything is correct. It's a real time-saver for anyone working with JSON and Java!
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