Add valid JSON
Paste an object or array, or open a local .json file. Nested structures and representative array records produce the best types.
Intelligent JSON type inference
JSON to Java Converter
Generate clean Java model classes from real JSON data. Infer nested objects, Lists, numeric types, nullable wrappers, and safe field names with optional getters and setters.
- Nested type inference
- Private browser processing
- Copy or download Java
JSON input
Generated Java0 bytes
How to convert JSON to Java
Generate reusable Java definitions in three focused steps.
Configure the class
Name the root model, choose whether to include accessors, and let the converter infer nested Java field types.
Export Java
Review the generated source, copy it into your project, or download a ready-to-use .java file.
Type inference designed for real API data
The generator examines complete structures rather than guessing from the first property alone.
Nested models
Objects inside objects receive clear named definitions instead of unreadable inline blocks.
Collection inference
JSON arrays become typed Java Lists, including Lists of generated nested model classes.
Jackson mappings
Invalid or reserved JSON property names receive safe fields with @JsonProperty annotations.
Private conversion
JSON parsing and type generation happen locally in your browser without a server upload.
How JSON becomes a Java model
Strings become String, whole numbers become Long, decimal numbers become Double, booleans become Boolean, arrays become typed List fields, and objects become nested model classes.
Safe deserialization names
JSON keys may contain hyphens, spaces, reserved Java words, or leading numbers. The generator creates a valid field identifier and adds @JsonProperty so Jackson can still map the original key.
Use representative JSON
Generated classes describe the sample you provide. Include realistic array records and nullable values so field types reflect the API payload accurately.
// JSON { "id": 42, "name": "Alex", "roles": ["admin", "editor"] } // Java public class Root { private Long id; private String name; private List<String> roles; }
JSON to Java converter FAQs
Practical details about inference, arrays, nulls, and generated definitions.
Does the converter support nested JSON?
Yes. Nested objects become static nested Java classes, and arrays of objects become typed Lists of generated classes.
How are arrays of objects handled?
Object samples are merged so the generated element class includes fields found across the supplied records.
What happens to null values?
Known nullable fields use Java wrapper or reference types. A value that is only null in the sample becomes Object because its concrete type cannot be inferred.
Can I generate getters and setters?
Yes. Keep the accessor option selected to create public getter and setter methods for every generated field.
Are invalid JSON property names supported?
Yes. The generator sanitizes the Java field name and adds a Jackson @JsonProperty annotation with the original key.
What type is generated for an empty array?
An empty array provides no element evidence, so the field is generated as List<Object>.
Is my JSON uploaded to the server?
No. Parsing, inference, copying, and downloading happen locally inside your browser.
Should generated types be reviewed?
Yes. The definitions describe the supplied sample. Compare them with your API contract, especially when optional or rare fields may be absent.