I have solved this problem.
I think it should be a bug in WTK 2.1
Another guy also asked the same question in sun forum, http://forum.java.sun.com/thread.jsp?thread=476073&forum=82&message=2209148
Here is how I solved it:
(OS: WinXP Pro+JDK1.4.2_03)
1. Uninstall the old WTK 2.1, delete all the files
2. Change My system's default Locale to English(U.S) (My original default is Chinese)
3. restart your computer
4. reinstall the WTK 2.1
Run the SMSDemo through OTA, It should be fine.
Very simple , but it waste me a lot of time. I have tried on a lot of machines to find whether it is a bug(Unfortunatly their default Locale are all Chinese) and debug the sun's source until I change my system Locale to English. In my understanding, the NullPointerException should be always a bug!
There days people are like to say "UNFAIR". Yes, it is unfair anywhere, the lack of testing
on other's language OS make it "UNFAIR" for none english speaking nations. (Just a joke, Unfair is too popular now)
[ February 25, 2004: Message edited by: Mike Wang ]