question: public final < E extends Throwable > Mono < T > otherwise ( Class < E > type , Function < ? super E , ? extends Mono < ? extends T > > fallback ) { Objects . requireNonNull ( type , "type" ) ; @ SuppressWarnings ( "unchecked" ) Function < ? super Throwable , Mono < ? extends T > > handler = ( Function < ? super Throwable , Mono < ? extends T > > ) fallback ; return otherwise ( null , handler ) ; }
target:  Subscribe to a returned fallback publisher when an error matching the given type occurs. <p> <img class="marble" src="https://raw.githubusercontent.com/reactor/projectreactor.io/master/src/main/static/assets/img/marble/otherwise.png" alt="">