public ConfigDefinition getDef(ConfigDefinitionKey defKey) {
        ConfigDefinition def = userConfigDefinitions.get(defKey);
        return (def != null) ? def : builtinConfigDefinitions.getConfigDefinitions().get(defKey);
    }
Cache that holds configs and config definitions (builtin and user config definitions).

@author vegardh
configserver/src/main/java/com/yahoo/vespa/config/server/ServerCache.java