A professional look does not come from using Java or any of the other useful and usable web languages for that matter.
If you want a professional look, you need to spend some time in graphics design, colour scheme selection and, most important of all, in the page and site layout.
The information the site is presenting (goods for sale, services offered, information presented and so on) are the most important features of any site that expects to do well. You can achieve this end result using plain old fashioned HTML or any one of the other web page languages.
Take a look at the BBC website for a professional looking site that does a wonderful job of presenting information to the public.