private static Optional<String> optionalInstallVariable(String name) {
        Optional<String> fromEnv = Optional.ofNullable(System.getenv((name.replace(".", "__"))));
        if (fromEnv.isPresent()) {
            return fromEnv;
        }
        return Optional.ofNullable(System.getProperty(name)); // for unit testing
    }
@author Tony Vaagenes
@author gjoranv
@author ollivir
standalone-container/src/main/java/com/yahoo/container/standalone/StandaloneContainerApplication.java