Servlets are one of the older APIs that is now part of Java Enterprise Edition (Java EE).
Look at JSF, Struts, Tapestry, Velocity, Shale, or any of the other Java EE or
Java based web frameworks and you will see servlets at the core.
The servlet API has stood the test of time because it was designed good from
the start and has evolved slowly. As part of Java EE 5.0 servlets
will be...
Most of the focus I seen in the AJAX world seems to revolve around the JavaScript and DHTML operations on the client. Without the 'X" in AJAX you really can't have any rich interaction.
At JavaOne there has been much talk about AJAX. There have been some discussions
about server-side AJAX components returning other content types than XML. Below
are two general models I see with AJAX today....