How does the tool name the Java fields?

JSON keys are converted to camelCase Java field names, for example first_name becomes firstName. If the converted name differs from the original key, a comment above the field shows the original JSON key.

What Java types does it use for numbers and strings?

Strings map to String, whole numbers map to Integer, decimal numbers map to Double, and booleans map to Boolean. Wrapper types are used instead of primitives so a field can also hold null.

How are nested objects handled?

Each nested object gets its own named class, generated from the property name (for example address becomes an Address class), and the parent field uses that class as its type.

What happens with an array of objects that have different fields?

The tool scans every item in the array and includes every field it finds across all items in the generated class, so no field is silently dropped.

Does the output include Jackson or Gson annotations?

No. The generated classes are plain Java with no external library dependency. Add annotations like @JsonProperty yourself if your JSON keys and Java field names differ and you use Jackson.

Is my JSON sent to a server?

No. Parsing and code generation run entirely in your browser with plain JavaScript. Your data never leaves your device.

JSON to Java

Paste JSON and instantly get matching Java POJO class definitions with getters, setters, and nested classes.

Input JSON

Root class name

Use isX() getters for booleans

Java Output

Paste JSON and click Generate

Copied!

Summary

JSON to Java reads a JSON value and generates matching Java class definitions, including private fields, public getters and setters, and separate classes for nested objects. When an array of objects is scanned, fields are gathered across every item so the generated class covers keys that only appear on some entries. Field names are converted to camelCase and the original JSON key is noted in a comment whenever it differs from the Java field name, so the mapping stays clear even without a JSON binding library.

How it works

Paste or type JSON into the input panel, or load a sample.
Set a root class name (defaults to RootObject).
Click Generate to parse the JSON and build Java classes.
Nested objects become their own named classes; arrays of objects are scanned across all items to collect every field.
Review the generated classes, each with private fields plus getters and setters, in the output panel.
Click Copy to copy the Java code to your clipboard.

Use cases

Scaffold a POJO for an incoming REST API response before writing a deserializer.
Turn a sample config file into a typed Java settings class.
Generate a starting class for Jackson or Gson without typing every field by hand.
Document a third-party API response shape as Java types.
Speed up building a Java client for an API that only ships JSON examples.
Check field naming and nesting before hand-writing a data model.

Frequently Asked Questions

Last updated: 2026-07-13 · Reviewed by Nham Vu