Java desktop app with Win XP look
I am very new to Java and I have a few questions regarding the possibilities of some things I am trying to achieve.
I am going to build a web-based application using PHP. There will be web services etc.. Except providing web based access I need 2 more types of clients for my application:
1) mobile phones - for making this client application I think I can use J2ME (can I consume web services from a J2ME application?)
2) desktop client application to run on multiple operating systems (Windows, Linux, Solaris etc..) - for making this client application I understood that I can use J2SE. Most of these clients will run on Windows. What I want to know is if it is possible to create the GUI to have the exact Windows XP look and feel when running on Windows XP for example. I will want the GUI to have Mac OS look and feel on Macs and so on.
This client is requested for Windows computers but if I could do with J2SE then I could stay free of .NET C# (which is how I'll have to do otherwise) and I could also run this desktop application on other operation systems preserving that operating system look and feel.
Is this possible with J2SE? If yes, what would be the performance losses on Windows compared to a .NET Windows desktop application?
Thank you very much for your answers.