Stefan,
Check the \ArcGIS 9.3.1\ArcGIS-Windows\ ArcGIS-931-filelist.htm for a list of all the file names and locations.
I found jar files in 9.3.1 -
\ArcSDE\GDBDirectConnect-Unix\ArcSDEDirectConnect\Disk1\InstData\Resource1.zip\$PROJECT_ROOT$\Source_StarTeam\ArcSDEDirectConnect...
I found several jar files in the 9.3 installation in :
GDBDirectConnect
Desktop\Documentation\License_Manager_Guide
Desktop\Documentation\install_guides
AcSDE_Personal
Hope this helps. The specific files you were looking for were not mentioned, likely because if you could find them you could provide their exact names 🙂
G