Struts 2 AJAX Autocomplete dropdown example

I started playing with struts 2.0.14 showcase application and thought of extracting a simple AJAX Autocomplete dropdown example from it.
In this example I am trying to create a autocomplete textbox and when you select one value from this autocomplete drop down the other will populate accordingly.

Struts 2.1.8 - FreeMarker template error! - Expression parameters.pushId is undefined

I was working on a simple Ajax autocomplete dropdown box and came across this error on Struts 2.1.8. Somehow all Struts 2 Freemarker errors are not clear at telling what is the root cause of a problem.

Search Web......