WebSphere Application Server - Express provides internal (built-in) servlets that you can add to your Web module to enable optional functions for that Web module.
Here are the available internal servlets:
com.ibm.ws.webcontainer.servlet.InvokerServlet
Invokes a servlet by class name. Add this servlet to a Web module with the WebSphere Development Studio for iSeries tools. For more information on how to add a servlet to your web module, see the WebSphere Development Studio Client Help.
org.apache.jasper.runtime.JspServlet
Enables the JSP page compiler for processing a Web module's JSP files.
com.ibm.ws.webcontainer.servlet.DefaultErrorReporter
Uses the extended error reporting function. See enhancing error reporting for more information.
com.ibm.servlet.PageListServlet
This servlet allows you to call a JSP file by name from within your servlet code. See Page lists for more information.
com.ibm.ws.webcontainer.servlet.SimpleFileServlet
Enables file serving for static files such as HTML and GIF files.