I have been creating vaadin application. I am using tomcat as application server. I need to access the project by using the URL like localhost:8080/webclient.
I need to change this like WWW.WEBCLIENT.COM. Is this possible in vaadin. Please give some suggestion.
This has nothing whatever to do with Vaadin, but is to do with how to deploy java web applications. It is impossible to give you more information without knowing how and where your application is going to run in production.
A general, broadbrush, approach :
install a java webcontainer (such as Tomcat) on a host that has the required domain name. (e.g. http://www.webclient.com)
Either install Apache2 and get it to forward requests to tomcat via mod_proxy OR reconfigure Tomcat to deploy the application as the root context and listen on port 80
More detail is probably best obtained through Google (Or your search engine of choice).