JSON to Java Class

Draft Jackson data classes from JSON

Java clients often need a POJO layer before Jackson can map an API response. This generator inspects a JSON object and writes a public root class with private fields, plus classes for nested object shapes. Whole numbers become long, decimal values become double, booleans become boolean, strings become String, and arrays become typed List fields when an example element is available.

For the default payload, User receives private long userId, private String name, and private boolean active. Because user_id differs from Java camel case, a JsonProperty annotation keeps the serialized key exact. A nested billing_address key becomes an annotated BillingAddress field and a matching child class, reducing the manual setup for Jackson-based clients or service tests.

Field mapping and follow-up work

The generated class deliberately stops short of inventing framework choices such as Lombok, records, constructors, or nullable annotations. Empty lists and nulls fall back to Object because one sample cannot establish a type. All parsing remains in your browser. Add accessors or Lombok annotations, then compare required and optional behavior with the service schema before using the class in production.