Do the generated classes work with Jackson out of the box?

Yes. Every field carries an @JsonProperty("originalKey") annotation so Jackson maps incoming JSON keys onto your camelCase Java fields without manual mappers. Just import com.fasterxml.jackson.annotation.JsonProperty.

How are nested objects handled?

Each unique object shape becomes its own public class. Names are inferred from property names (singularized for arrays of objects), giving you sensible defaults like User, Order, Comment that you can rename to fit your domain.

What about arrays of mixed types?

Mixed-type arrays produce List since Java doesn't have native unions. If you know the shape, refine to a more specific generic. PDFFlare doesn't try to invent sealed-type hierarchies from a single JSON sample.

Are integer vs floating-point types distinguished?

Yes. Whole-number values become long; decimal values become double. JSON treats both as 'number' but the converter inspects each value. For very small or very large integers you may want to swap long for int or BigInteger manually.

Does it generate getters and setters?

Yes — every field gets a paired get/set method (or is/set for booleans) following standard JavaBean conventions. That makes the classes work with any reflection-based library (Jackson, Gson with adapters, JPA, MapStruct, etc).

Why is the root class called Root?

A safe placeholder you can rename via the Root class field at the top of the tool, or with a project-wide find-and-replace. Trying to guess the right domain name from JSON usually picks the wrong noun.

Is the JSON sent to a server?

No. The conversion runs entirely in your browser — safe for production payloads, internal API responses, and JSON containing tokens or PII. Nothing leaves your device.

Can I use this with Gson, Moshi, or other JSON libraries?

The class structure is library-agnostic, but the @JsonProperty annotations are Jackson-specific. For Gson, swap @JsonProperty for @SerializedName. For Moshi, use @Json(name = "..."). The fields, types, and getters/setters work unchanged.

JSON to Java POJO — Free Online (Jackson)

JSON to Java POJO converter — generate Jackson @JsonProperty classes from any JSON sample. One class per shape, getters and setters, browser-based.

Generate Java POJOs from any JSON sample — one class per unique object shape, Jackson @JsonPropertyannotations preserving original keys, sensible type inference (long, double, boolean, List<T>). Paste the classes into your .java files and Jackson deserializes incoming JSON straight into typed objects.

Need C# instead? JSON to C#. Kotlin? JSON to Kotlin. TypeScript? JSON to TypeScript.

Root class

JSON

Java POJO

How to Generate Java POJOs from JSON

Paste a JSON sample
An API response, a webhook payload, or any JSON that represents the shape you want to model in Java.
Click Convert to Java
PDFFlare emits one POJO per unique object shape with @JsonProperty annotations preserving the original keys.
Drop into your project
Paste the classes into your .java files, rename Root to your domain type, and Jackson will deserialize incoming JSON straight into typed objects.

When Do You Need JSON to Java?

Typing a third-party REST API: The vendor docs are out of date. Hit the endpoint, copy the JSON response, paste here, get accurate Java classes that decode every field correctly.

Spring Boot @RequestBody: Generate the request DTO from a sample payload. Drop it into your controller, mark the parameter @RequestBody UserRequest, and Jackson handles the binding.

Webhook handlers: Stripe, GitHub, and similar services document webhook payloads as JSON examples. Convert each example to a typed Java POJO so your handler is compile-time safe instead of casting from Map<String,Object>.

Migrating from a dynamic language: Porting a Python or Node service to Java? Use real production payloads to seed the type definitions instead of guessing field names.

Why Use PDFFlare for JSON to Java?

Jackson Annotations Built In

Every field carries an @JsonProperty annotation preserving the original JSON key — no manual mappers, no renaming, no surprise nulls.

Smart Type Inference

long vs double inferred from the actual values. Arrays infer their element type when uniform; mixed types fall back to List<Object>.

100% Browser-Based

JSON samples stay on your device — safe for production payloads, internal API contracts, and tokenized responses.

No Signup Required

No account, no rate limits, no watermarks on the output.

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