We were using the mechanism of 'StartupItems' to create the service for the GECAMed server on Mac OSX. This mechanism has been marked as deprecated a few Mac OSX versions ago, and starting with Mac OSX 10.10 (Yosemite) it is no longer supported at all.
Now the recommended way to create a service on Mac OSX is to create a 'launchd' daemon.

Starting with GECAMed version 2.01.01 the installer and updater are using the new mechanism. If you have an older version and cannot update for some reason, you can also change it manually.

You'll need a user with administrator privileges to do the following operations.

1. Download the daemon definition and the JBoss control script: gecamed_launchd.zip
2. Extract the downloaded zip-file
3. Copy the extracted file “jboss_ctl.sh” into the folder “«GECAMed Install Dir»/jboss-4.0.5.GA/bin/”
4. Copy the extracted file “lu.tudor.santec.gecamed_server.plist” into the folder “/Library/LaunchDaemons/”
5. Open a terminal, to execute the following commands (commands to execute are bold)
6. Stop the JBoss server (only necessary, if the GECAMed server is running):
   sudo «GECAMed Install Dir»/jboss-4.0.5.GA/bin/jboss_ctl.sh stop
   By default, the «GECAMed Install Dir» is /Applications/GECAMed
7. Set the correct privileges for the daemon definition file:
   sudo chmod 644 /Library/LaunchDaemons/lu.tudor.santec.gecamed_server.plist
8. Register the daemon (this will also start the GECAMed server as service):
   sudo launchctl load /Library/LaunchDaemons/lu.tudor.santec.gecamed_server.plist
9. To avoid problems, delete the deprecated service definition:
   sudo rm -rf /Library/StartupItems/jboss
10. Check if the GECAMed server is running, then restart your system and check again