docker java mysql spring spring-boot

Trouble communicating between two docker containers

I’m new to docker and I’m trying to connect my spring boot app running into my boot-example docker container to a mysql server running into my mymysql docker container on port 6603, both running on the same phisical machine.
The fact is: if I connect my spring-boot app to my mymysql docker container in order to communicate with the database, I get no errors and everything works fine.

When I move my spring boot application into my boot-example container and try to communicate (through Hibernate) to my mymysql container, then I get this error:

2018-02-05 09:58:38.912 ERROR 1 --- [           main] o.a.tomcat.jdbc.pool.ConnectionPool      : Unable to create initial connections of pool.
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_111]

My spring boot are:


It works fine until my spring boot app runs in a docker container on port 8082, (after the docker image is correctly built):

docker run -it -p 8082:8083 boot-example