JSON to Java Class Converter

The JSON to Java Class Converter generates Java classes from a JSON sample so you can model an API response or configuration file without writing boilerplate by hand. You paste an object, and the tool produces a class for the top-level shape and a nested class for every embedded object, giving each field a sensible Java type inferred from the value it holds.

Type mapping follows Java conventions: strings become String, whole numbers become long, decimals become double, booleans become boolean, arrays become List of the element type, and objects become their own classes. When any list is present, the required import for java.util.List is added automatically. You can name the root class and choose whether to generate getter and setter methods for every field alongside the private declarations.

The converter works entirely in your browser, so the JSON you paste is never uploaded or stored. That keeps real payloads, internal field names, and sample data private while you iterate. It is free with no sign-up, so you can regenerate classes as often as you like as your data model evolves and paste the results straight into your project.

Features

• Generates a Java class for the root object and a separate class for each nested object.
• Maps JSON types to Java types: String, long, double, boolean, List and nested classes.
• Optionally emits standard getter and setter methods for every field in each class.
• Adds the java.util.List import automatically whenever any array is present in the data.
• Lets you set the root class name so the output matches your package and naming style.
• Uses safe field names, adjusting keys that are not valid Java identifiers.
• Runs fully in your browser with instant results you can copy or download.

How to use JSON to Java Class Converter

1. Paste a representative JSON object into the input box.
2. Enter the root class name you want to use.
3. Enable getters and setters if your project expects accessor methods.
4. Review the generated classes and confirm the inferred field types.
5. Copy the classes into your source tree, splitting them into files if needed.
6. Refine your JSON sample and regenerate whenever the data shape changes.

Benefits

• Java developers skip tedious POJO boilerplate when integrating a new API.
• Teams keep models consistent by generating classes directly from real responses.
• Getters and setters arrive ready for frameworks and serializers that expect them.
• Nested classes make complex, deeply structured payloads easy to work with.
• Automatic imports mean generated code is closer to compiling out of the box.
• Local processing keeps proprietary payloads and field names off any server.

The converter chooses long for whole numbers and double for decimals because those wider types safely hold most JSON numbers. If you know a field fits in a smaller type such as int or that a value should be BigDecimal for precision, adjust the field type after pasting. Likewise, numeric fields that are sometimes null in real data may be better modeled with boxed wrapper types like Long rather than primitives.

For each nested object, a dedicated class is generated and referenced by the parent, which mirrors how you would normally structure a Java data model. When you split the output into separate files, remember that each public class must live in a file that matches its name. You can also add annotations for your JSON library, such as field mapping or ignore annotations, once the skeleton is in place.

Because everything runs locally in your browser, there is no upload and no practical limit beyond your device memory, so you can paste large real-world responses. Review the generated types against your API documentation, especially for numbers and nullable fields, and treat the output as a strong starting point that you finish to match your exact requirements.