Does Java package has Model class?

Question

I found the following code below from http://java.sun.com/blueprints/guidelines/designing_enterprise_applications_2e/web-tier/web-tier5.html. The problem is there is no Model class during the java compilation. I thought it is included in the Java package. Anyway, I was fail to import the Model class from java.lang.Object, java.awt, java.awt.event.*, javax.swing.*, java.util.*, and so on. Does Model class belong to Java package or self create?
// Action.java:
public abstract class Action {
  protected Model model;
  public Action(Model model) { this.model = model; }
  public abstract String getName();
  public abstract Object perform(HttpServletRequest req);
// CreateUserAction.java:
public class CreateUserAction extends Action {
  public CreateUserAction(Model model) {
    super(model);
  public String getName() { return "createUser"; }
  public Object perform(HttpServletRequest req) {
    return model.createUser(req.getAttribute("user"),
                  req.getAttribute("pass"));
}

Answer 1

No, it's not a Java SDK class, and it doesn't self-create. It must be part of the blueprints download, so you'll have to find where it is (a JAR file you've downloaded, perhaps) and put it in the CLASSPATH.