In case the deployed docker container should contact a MQTT broker on a docker container hosted by the same machine, the two containers should share the same docker network in order to communicate properly.
See the commands below for a possible configuration of the two docker containers on the same host machine
First create a docker network
docker network create platynet
Then create the container with the MQTT broker as follows:
docker run --network platynet -p 1883:1883 --name mqtt-broker -v "$HOME/opt/mosquitto:/mosquitto" -it -d eclipse-mosquitto
Here we are assuming the mqtt broker use specific configuration file under the folder $HOME/opt/mosquitto/config requiring authentication to acccess the broker. You might test the broker using clients or applications like MQTT Explorer.
Create the container running the PLATINUm WS as Springboot application
docker run --network platynet -p 8080:8080 --name platinum_ws -it -d pstlab/platinum_ws
When the container is ready, simply access the container the install/run the java web application:
docker exec -it platinum_ws /bin/bash
/root/bin/install_and_run_platinum_ws