JSON से Java record.

Needs Java 16+ and jackson-databind 2.12+. Types are inferred from the sample only. Everything is calculated in your browser; nothing you type is uploaded.

Integers map to long, decimals to double, lists to List<T>; optional fields use Long, Double or Boolean so they can be null. Java keywords get a trailing underscore.

The sample becomes public record User(long id, @JsonProperty("user_name") String userName, …) with Order and Address nested inside.