I have never worked on android. I have to create a GWT/GXT web Application.
Will this application will look similar when viewed from Desktop, tablet(Windows/Android), Ipad.??
The response depend on how you have built your CSS. Did you use uibinder for HTML generation ? It's all about how you build your html and how you add styles to our HTML. At the end GWT generates HTML elements for which you will apply your custom CSS. The way it will look like is dependent to you CSS files. If you do nothing by default you should have the same rendering unless you use some third party components that handles internally a responsive design