JSON to Java Class
Generate POJO-style Java classes from JSON with nested object and array type inference.
What is JSON to Java Class?
Infer Java DTO structure from a JSON example. One payload cannot establish which properties are optional, all possible array shapes or the intended width of a numeric identifier.
How to use JSON to Java Class?
Step 1
Paste sample JSON into the input panel.
Step 2
Set the root class name and generate the class output.
Step 3
Copy the generated code and adapt naming or annotations as needed.
Example input / output
A customer payload with a nested address suggests separate DTO structure. Include nulls, missing optional fields and multiple array elements before choosing Java types and annotations.
Example input
{"id":42,"name":"Debug Tool","active":true,"tags":["json","java"],"owner":{"id":7,"email":"team@example.com"}}Check the result
- Mixed-type arrays lead to generic fallback types.
- Generated classes are scaffolding and may still need annotations, nullability, or domain-specific refinements.
Practical developer examples
Resolve ambiguous numbers
Decide whether a field is an integer, decimal amount, identifier or timestamp. Use BigDecimal for domain amounts where required; sample inference alone cannot choose business precision.
Review Java names
JSON keys may contain spaces, hyphens or reserved words. Check generated member names and add serialization annotations matching the original JSON names.
Common developer use cases
Generated classes need review for package names, imports, nullable fields and library conventions. A DTO does not validate authorization or business rules.
Common issues
FAQ
Can one sample define optional fields?
No. Presence in the sample is not proof that the contract requires a field.
Can I use the output unchanged?
Compile it in your project, verify serializer settings and test with representative payloads first.