What do you mean by ms...jar??
P.S. I am not Mint user. I use ubuntu.
Try to troubleshoot:
1. Did you chmod +x the jar file. Linux won't let Mineshafter-launcher.jar won't start unless it has executable permission. Ubuntu command is `chmod +x /path/to/mineshafter.jar`
2. Jar is opened via java. If you have no java runtime, It won't run. Google how to install openjdk. Last time I checked Ubuntu command is `sudo apt install openjdk-8-jre`