No instance(s) of type variable(s) T exist so that Flux<T> confirms to Mono<? extend R) - spring-boot

Question

I am implementing Spring webflux demo application and have written my demo application as like that
package com.abcplusd.application;
import com.abcplusd.domain.Event;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.http.MediaType;
import org.springframework.web.reactive.function.client.WebClient;
import reactor.core.publisher.Flux;
import java.util.Collections;
import java.util.Date;
import java.util.stream.Stream;
#SpringBootApplication
public class ReactiveClientApplication {
#Bean WebClient webClient() {
return WebClient.create("http://localhost:8080");
}
#Bean CommandLineRunner demo(WebClient webClient) {
return args -> {
webClient.get()
.uri("/events")
.accept(MediaType.TEXT_EVENT_STREAM)
.exchange()
.flatMap(clientResponse -> clientResponse.bodyToFlux(Event.class))
.subscribe(System.out::println);
};
}
public static void main(String[] args) {
new SpringApplicationBuilder(ReactiveClientApplication.class)
.properties(Collections.singletonMap("server.port", "8081"))
.run(args);
}
}
It shows the following error
Error:(29, 41) java: incompatible types: no instance(s) of type variable(s) T exist so that reactor.core.publisher.Flux<T> conforms to reactor.core.publisher.Mono<? extends R>
The above error is at this line:
.flatMap(clientResponse -> clientResponse.bodyToFlux(Event.class)))
Event Class
import lombok.AllArgsConstructor;
import lombok.Data;
import java.util.Date;
#Data
#AllArgsConstructor
public class Event {
private long id;
private Date when;
}
Can anybody help me to solve the error?

Answer 1

It works me after i have done these changes in my code
.flatMap(clientResponse -> clientResponse.bodyToFlux(Event.class)))
to
.flatMapMany(clientResponse -> clientResponse.bodyToFlux(Event.class))
and
#NoArgsConstructor annotation in Event.Class
as follows:
import java.util.Date;
#Data
#AllArgsConstructor
#NoArgsConstructor
public class Event {
private long id;
private Date when;
}

Answer 2

flatMapMany instead of flatMap works.
However when you add property spring.main.web_environment=false to application.properties file, webClient simply doesn't work.