JQuery UI datepicker doesn't work in a struts 2 ajax page

If you use struts2 dojo plug-in to get Ajax supports
Ty the parameter executeScripts="true"

Reason for java.lang.InstantiationException

When I was adding a new DTO class, I was came up "* java.lang .InstantiationException*". So I had little bit annoyed but I found that the default constructor is missing.