private IllegalArgumentException createInvalidMappingError(String mapping, Exception exp) {
        return new IllegalArgumentException("\nInvalid port mapping '" + mapping + "'\n" +
                "Required format: '<hostIP>:<hostPort>:<containerPort>(/tcp|udp)'\n" +
                "See the reference manual for more details");
    }
Return the content of the mapping as an array with all specifications as given

@return port mappings as JSON array or null if no mappings exist
src/main/java/io/fabric8/maven/docker/access/PortMapping.java