private String resolveHostname(String bindToHost) {
        try {
            return InetAddress.getByName(bindToHost).getHostAddress();
        } catch (@SuppressWarnings("unused") UnknownHostException e) {
            throw new IllegalArgumentException("Host '" + bindToHost + "' to bind to cannot be resolved");
        }
    }
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