Here is an example of how to use the DoubleNode class from the com.fasterxml.jackson.databind package in the Jackson library for Java:

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.DoubleNode;

public class Main {
    public static void main(String[] args) {
        JsonNode node = new DoubleNode(3.14);
        System.out.println(node.asDouble()); // prints 3.14
    }
}

In this example, we first import the JsonNode and DoubleNode classes from the com.fasterxml.jackson.databind package. Then, we create a new DoubleNode object with the value of 3.14 and assign it to a variable of type JsonNode. Finally, we print the value of the node using the asDouble() method, which returns the value of the node as a double.