Here is a basic example of how to use the MappingIterator class in the com.fasterxml.jackson.databind package in Java:

import com.fasterxml.jackson.databind.MappingIterator;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.JsonNode;

import java.io.File;
import java.util.List;

public class Example {
    public static void main(String[] args) throws Exception {
        ObjectMapper mapper = new ObjectMapper();
        MappingIterator<JsonNode> iterator = mapper.readValues(new File("example.json"), JsonNode.class);
        while (iterator.hasNext()) {
            JsonNode node = iterator.next();
            // do something with the node
        }
    }
}

In this example, we are importing the MappingIterator and ObjectMapper classes, as well as the JsonNode class from the com.fasterxml.jackson.databind package. We then create an instance of the ObjectMapper class, and use its readValues method to read the contents of a JSON file and return a MappingIterator of JsonNode objects.

We then use the hasNext() method to check whether there are more elements to iterate over, and the next() method to retrieve the next element. The iterator will stop when there are no more elements to iterate over.

This is just a basic example of how to use the MappingIterator class. You can also use it to read json from a stream, string, etc.