Free online JSON to Java class generator. Paste JSON and generate Java POJO classes or records with getters/setters, @Nullable annotations, and nested type support automatically. 100% browser-based with zero uploads.
100% browser-based — your data never leaves your device
Convert JSON to Java POJO classes instantly. Generate Java records or classes with getters and fields from JSON samples.
Copy your JSON data and paste it into the input textarea above.
Toggle record mode, nullable detection, and package naming preferences.
Click Generate, then copy the Java classes or download the .java file.
Drop a file here or click to browse
Ctrl+Enter to generate
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This generator produces Java POJO classes or Java 16 and newer records from a JSON sample, running entirely in your browser. JSON types map to Java types automatically, and nested objects become separate static inner classes.
Getters are generated in POJO mode, while record mode emits the compact record syntax for immutable data carriers.
REST client libraries and service layers need data transfer objects that mirror the JSON they consume, and this generator produces them from an actual response sample. Instead of writing boilerplate classes by hand, you generate POJOs or records that match the payload exactly, which is the standard workflow when building client libraries against a documented contract. The same approach covers DTOs from data contracts and rapid prototyping of class hierarchies from a JSON schema.
Mode choice matters. POJO mode targets Java 8 and newer with private fields and getter and setter patterns, which persistence frameworks expect when they mutate entities. Record mode targets Java 16 and newer with compact syntax and value semantics, ideal for immutable data carriers where constructor, equals, hashCode, and toString come for free. Nullable fields can be annotated or wrapped, and package naming keeps the output organized for your module.
Enterprise JSON payloads routinely carry customer records, account details, and internal identifiers, and the DTOs you generate mirror that data exactly. Sending the sample to an online generator exposes your enterprise data structures to an external service.
This JSON to Java generator works entirely in your browser, so sample data never leaves your device. You can generate enterprise DTOs and client models while keeping your data contracts private.
Copy your JSON data and paste it into the input textarea above.
Toggle record mode, nullable detection, and package naming preferences.
Click Generate, then copy the Java classes or download the .java file.
Practical examples to help you get the most out of JSON to Java:
// JSON:
// {"id": 1, "name": "Alice", "email": "alice@example.com"}
// Generated Java:
// public class User {
// private int id;
// private String name;
// private String email;
// public int getId() { return id; }
// public void setId(int id) { this.id = id; }
// // ... getters and setters
// }// JSON:
// {"name": "Alice", "age": 30}
// Generated Java record:
// public record User(String name, int age) {}Java records are immutable. Use POJO mode if you need setters for frameworks like JPA/Hibernate or Jackson deserialization with mutation.
JSON numbers always become int/double. Review and adjust to long, BigDecimal, or other types based on your actual data range.
POJO mode targets Java 8+ with standard getter/setter patterns. Record mode targets Java 16+ with the compact record syntax.
Nested objects become separate static inner classes within the main class, with proper type references between them.
No. All conversion happens locally in your browser.
Yes. Enable record mode to generate Java 16+ records with compact syntax, ideal for immutable data carrier objects.
Generate traditional POJO classes with private fields and getters, or modern Java 16+ records.
Automatically maps JSON types to Java types: String, Integer, Double, Boolean, List, Map, and nested class references.
Fields with null values use @Nullable annotation or Optional<T> wrapper types.
All conversion happens in your browser — your data stays private.
JSON to Java Class Generator is useful in a variety of scenarios across different workflows:
Generating Java POJOs from API response JSON for REST client libraries
Creating data transfer objects (DTOs) from sample data contracts
Rapid prototyping of Java class hierarchies from JSON schemas
Java records are ideal for data carrier objects. Enable record mode when you only need immutable data with constructor, equals, hashCode, and toString.
Enable nullable detection and @Nullable annotations to document which fields may be null, improving code safety and IDE support.
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