Something

err=1
until [ $err == 0 ];
do
        mv log/java0.log "log/`date +%Y-%m-%d_%H:%M:%S`-java.log" >/dev/null 2>&1
        mv server.log "log/server-`date +%Y-%m-%d_%H:%M:%S`.log"
        nice -n -3 java -Xms512m -Xmx768m -cp bsf.jar:bsh-2.0.jar:jython.jar:c3p0-0.9.0.jar:mysql-connector-java-3.1.10-bin.jar:l2jserver.jar net.sf.l2j.Serve
r > server.log 2>&1
        err=$?
        /etc/init.d/mysql restart
        sleep 30;
done