jRDC jar file now running smoothly on ubuntu server with mysql. The problem with my environment was that i ended up with two versions of jre(8 and 9), the system was not configured to select default jre. I executed sudo update-alternatives --config java and select number 2 with jre 9 and on running nohup java -jar /usr/local/bin/jRDC.jar, the server is now up and processing my querries fast and furious, am happy, thanks so much aeric, cheers cheers cheers!!