JSON → Java classes

Client

Public fields and List types for quick paste into your project—tune for your style guide.

Learn more: JSON and Java

Paste a sample JSON object to generate simple Java field declarations that mirror its structure—a starting point for Jackson, Gson, or manual parsing.

JSON on the JVM

Java libraries map JSON objects to classes or to generic maps and lists. Field names in JSON align with Java field or property names; nested objects become nested classes or separate types.

From sample to code

The generator infers names and basic types from one example. Real APIs may add optional fields or unions—adjust access modifiers, use boxed types for nullable values, and add getters/setters to match your style.

Scope

Like the C# sibling page, this flow is JSON → Java scaffolding, not a full round-trip from arbitrary Java sources into JSON definitions.

JSON → Java

?

Parses JSON in your browser and emits classes inferred from the sample shape. Nested objects become nested types; arrays use the first element only to guess item shape. Nothing is uploaded.

Rename types, tighten numeric types, and add annotations for your serializer (Gson, Jackson, etc.) as needed.

Common use cases

  • Sketch POJO-style classes for Jackson or Gson before adding annotations and builders.
  • Compare inferred List and nested types with OpenAPI-generated models.
  • Paste sample microservice payloads into starter classes for spike code.

Common mistakes to avoid

  • Using raw List without element generics in real code

    Tighten generic parameters to match your DTOs; generated lists are a hint, not production-ready signatures.

  • Ignoring BigDecimal for money fields

    JSON numbers may map to double in samples—use BigDecimal or strings for currency when appropriate.

FAQ

Is Java generation performed locally?

Yes. All inference happens in your browser.

Does this generate records instead of classes?

Output is simple class-style scaffolding. Convert to records or immutability patterns to match your JDK and style guide.

More tools

Related utilities you can open in another tab—mostly client-side.