title: Change themes in Vaadin 7 via code
body: <p>I am doing a project in Vaadin 7. In that I need to change the theme of a page.</p>
  
  <p>In Vaadin 6, there is a function called 'setTheme()'. so that I can change the theme using that function wherever I want in my code.</p>
  
  <p>But, In Vaadin 7, I couldn't find any like that.</p>
  
  <p>I know there will be a way to do it. </p>
  
  <p>And also how to apply changes on the UI when I change a theme?</p>
  
  <p>Will it be changed automatically? (or)</p>
  
  <p>ICEPush gonna help me?</p>