archaius-core/src/main/java/com/netflix/config/ConfigurationWithPollingSource.java
@Override
    public Double getDouble(String key, Double defaultValue) {
        return config.getDouble(key, defaultValue);
    }
@Override
    public Double getDouble(String key, Double defaultValue) {
        return config.getDouble(key, defaultValue);
    }
Delegates to the underlying configuration.