private void addEnvironment(Properties envProps) {
        JsonArray containerEnv = new JsonArray();
        Enumeration keys = envProps.keys();
        while (keys.hasMoreElements()) {
            String key = (String) keys.nextElement();
            String value = envProps.getProperty(key);
            if (value == null) {
                value = "";
            }
            containerEnv.add(key + "=" + value);
        }
        createConfig.add("Env", containerEnv);
    }
Get JSON which is used for <em>creating</em> a container

@return string representation for JSON representing creating a container
src/main/java/io/fabric8/maven/docker/access/ContainerCreateConfig.java