Cannot construct Spring webClient due to java.lang.IllegalStateException: No suitable default ClientHttpConnector found

Question

I would like to use a specific WebClient in my service class. I get this exception while constructing it:

It looked like it was a dependency issue but a good old clean-install didn't change anything.

Do I need to specify manually a Bean in my configuration?

Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.***.Client]: Constructor threw exception; nested exception is java.lang.IllegalStateException: No suitable default ClientHttpConnector found
        at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:213)
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:117)
        at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:310)
        ... 122 more
    Caused by: java.lang.IllegalStateException: No suitable default ClientHttpConnector found
        at org.springframework.web.reactive.function.client.DefaultWebClientBuilder.getOrInitConnector(DefaultWebClientBuilder.java:266)
        at org.springframework.web.reactive.function.client.DefaultWebClientBuilder.build(DefaultWebClientBuilder.java:244)
        at com.***.Client.<init>(Client.kt:35)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        at kotlin.reflect.jvm.internal.calls.CallerImpl$Constructor.call(CallerImpl.kt:41)
        at kotlin.reflect.jvm.internal.KCallableImpl.call(KCallableImpl.kt:106)
        at kotlin.reflect.jvm.internal.KCallableImpl.callDefaultMethod$kotlin_reflection(KCallableImpl.kt:152)
        at kotlin.reflect.jvm.internal.KCallableImpl.callBy(KCallableImpl.kt:110)
        at org.springframework.beans.BeanUtils$KotlinDelegate.instantiateClass(BeanUtils.java:788)
        at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:185)

My class is simply:

@Service
class Client {
    private val webClient = WebClient.builder()
            .baseUrl("https://****.com/")
            .defaultHeader(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE)
            .build()
}

In my pom.xml file:

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-mail</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>org.springframework.ws</groupId>
            <artifactId>spring-ws-core</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webflux</artifactId>
        </dependency>

Answer 1

I found the problem: it turns out that netty dependencies were missing, as I imported the maven artifact that has WebClient but not the rest...

Replacing:

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-webflux</artifactId>
</dependency>

with:

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-webflux</artifactId>
</dependency>

solved it.

Answer 2

As an alternative to Léo Schenider answer, you don't need to replace spring-webflux with spring-boot-starter-webflux (what adds some additional dependencies you don't need), you just need to include:

<dependency>
    <groupId>io.projectreactor.netty</groupId>
    <artifactId>reactor-netty-http</artifactId>
</dependency>

And leave spring-webflux as it.