>However, if I would like choose a language like C# or Java my prefer will Java. Because;
>
>1- Java is really platform independent language.

Not really, see http://www.adtmag.com/article.asp?id=4130 and http://www.wsdmag.com/Articles/ArticleID/6582/6582.html
There are plans to port the .NET framework on other platforms, like Linux (http://www.go-mono.com/)

>2- Maybe one day Billy wakes up and he decide to "C# is over"

Contrary to Java and VB which are property of Sun and Microsoft, C# is now a standard. See http://www.windowsfordevices.com/news/NS6480940104.html and http://msdn.microsoft.com/net/ecma/