Servlets are Java classes which service HTTP requests. The only requirement for writing a servlet is that it implements the javax.servlet.Servlet interface.

Servlets are loaded from the classpath like all Java classes. Normally, users put servlets in WEB-INF/classes so Resin will automatically reload them when they change.

JSP pages are implemented as Servlets, and tend to be more efficient for pages with lots of text.

Resin provides a set of convenient servlets in the com.caucho.servlets.* package.

WebDAV, web-based distributed authoring and versioning, is a set of extensions to the HTTP protocol that is a convenient replacement for FTP when developing web sites. Many editing tools can save to a WebDAV server directly and several operating systems can provide a filesystem to a WebDAV server.

Some web applications need a task to be run at regular intervals, e.g. once an hour or once a day. For example, a search application might want to spider the web site every day to automatically pick up any new pages. Syndication applications might poll their news sites every hour to check for updates.

Resin provides a set of convenient filters in the com.caucho.filters.* package.