The core Wicket package. The key core classes you will need to learn to do basic Wicket programming are:

• Application / WebApplication - Subclass WebApplication to create your application. Set your home page with Application.getPages().setHomePage(MyHomePage.class). Configure Wicket for deployment with Application.getSettings().configure("deployment"). Substitute "development" to get default settings for a development environment.
• Component - You will need to carefully study this class as Component is very central to Wicket. There are a large number of convenience methods in Component and, naturally, every component in Wicket is a subclass of Component, so all these methods are available to all Components.
• IRequestCycleFactory - If you are working with a persistence framework such as Hibernate or JDO, you may need to implement a request cycle factory in order to open a persistence session at the beginning of a request and close the session at the end of the request.
• ISessionFactory - For all but the most trivial applications, you will need to create your own session factory. Your implementation of this interface will generally be quite simple, generally just returning a new instance of your own application-specific subclass of WebSession.
• MarkupContainer - You will need to study MarkupContainer carefully as this class contains all the logic for creating and maintaining component hierarchies.
• Page / WebPage - Every page in your wicket application will extend WebPage (or some other subclass of Page if you are writing something other than a web application). There are a number of important methods in Page and you should be familiar with all of them.
• PageParameters - A simple wrapper for query string parameters.
• Session / WebSession - It is particularly important to understand Session if you are doing clustering, but even for a very basic application you will want to create your own subclass of WebSession using a session factory so that you can store any session properties in a typesafe way. Note that since Pages are first class objects with models of their own, it is likely or at least possible that you will not have many session properties.