This tutorial will lead you to setup a simple JSP hosting on Ubuntu machine. You may want to consider this as a basic setup to host any of your web application which developed using Java - JSP or Servlet, Tomcat and MySQL
Flex can make requests to your existing JSPs using the HTTPService object. These requests can work with any JSPs. A Flex application contains all of the view logic so the JSPs should not return HTML but rather just serialized data
AjaxTags makes it very easy for you to add powerful Ajax features to either new or existing Java Web applications. With a full complement of JSP tags providing support for drop-down box modifications, toggling, tab panels, callouts, etc.
This article looks at the unified expression language (EL), which has been added to the JavaServer Pages Standard Tag Library (JSTL) specification in order to overcome problems when integrating the JavaServer Pages (JSP) EL with the JavaServer Faces EL.
The expert groups have worked together on the upcoming releases of JSP 2.1 and JavaServer Faces 1.2 technologies in Java EE 5 to fix these integration issues and make sure that the two technologies work together seamlessly.
Several tutorials are available to help you get started with the framework, from all-purpose "soup to nuts" tutorials to specialty tutorials on portlets and database access.