Java Message Stream??

[dw85745]

I'm trying a workaround for a server logon that was written in JAVA.
The Java program is initiated from the command line (a string of jar files)
and then pops a logon screen. Rather than manually entering user ID and password I want to have my program to enter this information
into the logon textboxes.

Spy++ (Microsoft) finds the logon form, but is unable to locate any controls on the form, including textboxes.
I thought Java used the OSes controls -- hence platform independent??

Question:
1) Will Spy++ work on JAVA?
2) Does JAVA use Miscrosofts message stream if it is running on XP for example?