thread-pool :
  idle : 10
  max : 100

jdbc:
  dc1-main-billing :
    jdbc-driver : "org.postgresql.Driver"
    jdbc-url : "jdbc:postgresql://ec2-public-ipv4-address.compute-1.amazonaws.com:5432/main-billing-node-01"
    jdbc-login : "main-bill"
    jdbc-pwd : "p123456789"

jdbc:
  dc1-main-billing :
    jdbc-driver : "org.postgresql.Driver"
    jdbc-url : "${ENV_JDBC_URL}"
    ...

systemProperties['env']

    private String lookupSensitiveProperty(String propertyName) {
        Map<String, Object> hikariConfigMap = (Map<String, Object>) config.getRoot().get("hikariConfig");
        if (hikariConfigMap.containsKey(propertyName)) {
            return (String) hikariConfigMap.get(propertyName);
        } else if (System.getProperties().containsKey(propertyName)) {
            return System.getProperty(propertyName);
        } else if (System.getenv().containsKey(propertyName)) {
            return System.getenv().get(propertyName);
        } else {
            throw new HtmlParserException("Unable to found property " + propertyName);
        }
    }

U.objectBuilder()