Java JsonIdentityReference-class And Method Code Example

I apologize, but I must inform you that there is no JsonIdentityReference class in the Apache Commons IO library. This library provides a set of I/O utilities such as file manipulation, file filters, and file comparators, but it does not have any specific functionality for working with JSON.

If you are looking for a way to handle JSON serialization and deserialization with identity references in Java, you can use a third-party library such as Jackson. Here is an example using the Jackson library with the JsonIdentityInfo and JsonIdentityReference annotations:

import com.fasterxml.jackson.annotation.JsonIdentityInfo;
import com.fasterxml.jackson.annotation.JsonIdentityReference;
import com.fasterxml.jackson.annotation.ObjectIdGenerators;
import com.fasterxml.jackson.databind.ObjectMapper;

@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")
class Person {
    private int id;
    private String firstName;
    private String lastName;
    @JsonIdentityReference(alwaysAsId = true)
    private Person manager;

    public Person(int id, String firstName, String lastName, Person manager) { = id;
        this.firstName = firstName;
        this.lastName = lastName;
        this.manager = manager;

    // Getters and setters
    // ...

public class JsonIdentityReferenceExample {
    public static void main(String[] args) throws IOException {
        Person john = new Person(1, "John", "Doe", null);
        Person jane = new Person(2, "Jane", "Doe", john);
        Person jim = new Person(3, "Jim", "Smith", jane);

        // Create an ObjectMapper instance
        ObjectMapper mapper = new ObjectMapper();

        // Serialize the object to a JSON string
        String json = mapper.writeValueAsString(jim);

        // Print the JSON string

        // Deserialize the JSON string back to an object
        Person jim2 = mapper.readValue(json, Person.class);

        // Print the object

This example uses the JsonIdentityInfo and JsonIdentityReference annotations to specify that the id property should be used as the identity property when serializing and deserializing the Person class. The JsonIdentityReference annotation with the alwaysAsId property set to true, will serialize the reference property as an id rather than serializing the full object.

When you run this example, you will see that the manager property is serialized as a reference to the id property, rather than as a full copy of the object.

Note that this annotation is used in combination with the ObjectIdGenerators class.

Also other libraries like Gson can handle this situation as well.