private static Optional<ConfigItem> resolveConfig( final String prefix, final ConfigDef def, final String propertyName) { if (!propertyName.startsWith(prefix)) { return Optional.empty(); } final String keyNoPrefix = stripPrefix(propertyName, prefix); final ConfigKey configKey = def.configKeys().get(keyNoPrefix); if (configKey == null) { return Optional.empty(); } return Optional.of(ConfigItem.resolved(configKey)); }