Here is an example of using the @JsonAnySetter annotation from the com.fasterxml.jackson.annotation package in the Jackson JSON library to handle unknown properties during deserialization:

import java.util.HashMap;
import java.util.Map;

import com.fasterxml.jackson.annotation.JsonAnySetter;

public class MyClass {
    private Map<String, Object> additionalProperties = new HashMap<String, Object>();

    public Map<String, Object> getAdditionalProperties() {
        return this.additionalProperties;
    }

    @JsonAnySetter
    public void setAdditionalProperties(String name, Object value) {
        this.additionalProperties.put(name, value);
    }
}

In this example, the @JsonAnySetter annotation is used to indicate that the setAdditionalProperties method should be used to handle any unknown properties during deserialization. The method takes two arguments: the name of the unknown property and its value. The method then adds the property and its value to the additionalProperties map.

Here is how you can use the above class

import com.fasterxml.jackson.databind.ObjectMapper;

public class Main {
    public static void main(String[] args) throws Exception {
        String json = "{\"property1\":\"value1\",\"property2\":\"value2\",\"unknownProperty\":\"unknownValue\"}";
        ObjectMapper mapper = new ObjectMapper();
        MyClass myObject = mapper.readValue(json, MyClass.class);
        System.out.println("Additional Properties : "+myObject.getAdditionalProperties());
    }
}

In this example, the JSON string contains two known properties property1 and property2, and one unknown property unknownProperty. The deserialization process will set the values of the known properties on the corresponding fields in the MyClass object. The unknown property will be handled by the setAdditionalProperties method and added to the additionalProperties map.