That was the minecraft_server.jar output and not the clients one.
Why should I do anything with the client if I couldn't start the server and cant try to connect with my modded client?
Do I need any client stuff installed on the debian server?
Hey,
downloaded a fresh minecraft_server.jar and tryed http://jenkins.minecraftforge.net:7070/job/forge/ build 234 , 230 and 200.
Extracted everything into the server_jar and started the server on a Debian vserver minimal with
java -Xmx1536M -Xms1536M -jar minecraft_server.jar -nogui 2>&1 | tee -a server.log
Output: