public static DB getConnection(String instance) {
        if(Objects.isNullOrEmpty(instance))
            instance = DEFAULT_INSTANCE;
        if(!connections.containsKey(instance)){
            initialize(instance);
        }
        return connections.get(instance);
    }
public static DB getConnection ( String instance ) { if ( Objects . isNullOrEmpty ( instance ) ) instance = DEFAULT_INSTANCE ; if ( ! connections . containsKey ( instance ) ) { initialize ( instance ) ; } return connections . get ( instance ) ; }
Get connection

@param instance
@return