You cannot "run WPF application in Java" if by Java you mean Java machine. If you want to develop .NET applications using Java, it's possible.
One implementation of Java for .NET is IKVM.NET, see
http://www.ikvm.net/[
^].
Another product is Ja.NET, see
http://www.janetdev.org/[
^].
Also, Microsoft use to bundle Visual Studio (2005) with J# — a .NET language with Java syntax, see
http://msdn.microsoft.com/en-us/vjsharp/bb188593[
^]. I don't know what is the status of this product right now; please find out yourself if you're interested.
Look at the list of CLI languages here:
http://en.wikipedia.org/wiki/.NET_languages[
^].
—SA