git clone https://github.com/chnyangjie/ib-gateway-demo.git
cd ib-gateway-demo
mvn package -Dmaven.test.skip=true -X
assume your gateway is running on localhost 14444
java -jar gateway-demo-jar-with-dependencies.jar 127.0.0.1 14444 1
the 1st argument is the IP of gateway process
the 2nd argument is the port of gateway process
the 3rd one is client id, which should be an integer, if you don't know what it means, just use 1 will be fine.