gistfile1.txt

@Test
        public void fluxErrorHandling(){

            Flux<String> stringFlux = Flux.just("a","b","c")
                    .concatWith(Flux.error(new RuntimeException("Exception Occurred")))
                    .concatWith(Flux.just("D"))
                    .onErrorResume((e) -> { // on error this block gets executed - we are returning a flux on error value
                        System.out.println(e);
                        return Flux.just("default");
                    });

            StepVerifier.create(stringFlux.log())
                    .expectSubscription()
                    .expectNext("a","b","c")
                    .expectNext("default")
                    .expectError(RuntimeException.class)
                    .verify();

        }