NumberDeserializers is a class in the Jackson library that contains a set of pre-built deserializers for several common number types like Integer, Long, Float, Double, etc.

It is not meant to be instantiated or subclassed by the user, it is used by the ObjectMapper class to register deserializers for number types.

Here is an example of how you can use NumberDeserializers to configure a ObjectMapper instance to use custom deserializers for certain types:

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;

public class Main {
    public static void main(String[] args) {
        ObjectMapper mapper = new ObjectMapper();
        SimpleModule module = new SimpleModule();
        module.addDeserializer(Integer.class, new CustomIntegerDeserializer());
        module.addDeserializer(Long.class, new CustomLongDeserializer());
        mapper.registerModule(module);
    }
}

In this example, a SimpleModule is created and it is used to register custom deserializers for Integer and Long types using the addDeserializer method.

The SimpleModule is then registered with the ObjectMapper instance using the registerModule method.

It is using custom deserializers provided by the user, but it also uses NumberDeserializers internally to deserialize other number types.

Note: The custom deserializers CustomIntegerDeserializer and CustomLongDeserializer are not provided in this example, you will have to create them.