JSON to Java Class Converter: Generate POJOs from JSON Data

Converting JSON responses to Java classes is one of the most common tasks in Java backend development. Here's how to do it efficiently.

The Problem

When consuming REST APIs, you need Java classes that match the JSON response structure. Manually writing POJOs for nested JSON objects is time-consuming and error-prone.

{
  "id": 1,
  "name": "John Doe",
  "email": "[e-mail]",
  "address": {
    "street": "123 Main St",
    "city": "Springfield",
    "zipCode": "62701"
  },
  "orders": [
    { "orderId": "A001", "total": 29.99 }
  ]
}

Automatic Generation

Instead of writing classes by hand, use the JSON to Java Converter to instantly generate:

• POJO classes with private fields
• Getters and setters for each field
• Constructors (default + parameterized)
• Nested classes for nested objects
• List types for arrays
• Proper Java types (String, int, double, boolean)

Example Output

public class User {
    private int id;
    private String name;
    private String email;
    private Address address;
    private List<Order> orders;

    // Getters and setters
    public int getId() { return id; }
    public void setId(int id) { this.id = id; }
    // ...
}

Tips for Java JSON Handling

1. Use Jackson for serialization: ObjectMapper mapper = new ObjectMapper()
2. Add @JsonProperty for fields with different JSON names
3. Use @JsonIgnoreProperties(ignoreUnknown = true) for forward compatibility
4. Consider records in Java 16+: record User(int id, String name) {}

Related Tools

• JSON to Kotlin - Generate Kotlin data classes
• JSON to TypeScript - Generate TS interfaces
• JSON Formatter - Format and validate JSON