How to Disable Spring Web MVC - spring-boot

Question

Hi I've just upgraded springboot from 2.0.5 to 2.1.8
First I got this error
The bean 'requestMappingHandlerAdapter', defined in class path resource [org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class], could not be registered. A bean with that name has already been defined in org.springframework.web.reactive.config.DelegatingWebFluxConfiguration and overriding is disabled.
So, I added this in application.properties
spring.main.allow-bean-definition-overriding: true
However I got different error.
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.web.reactive.config.DelegatingWebFluxConfiguration': Initialization of bean failed; nested exception is java.lang.IllegalStateException: The Java/XML config for Spring MVC and Spring WebFlux cannot both be enabled, e.g. via #EnableWebMvc and #EnableWebFlux, in the same application.
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:601) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:845) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:877) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.1.8.RELEASE.jar:2.1.8.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:744) [spring-boot-2.1.8.RELEASE.jar:2.1.8.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:391) [spring-boot-2.1.8.RELEASE.jar:2.1.8.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:312) [spring-boot-2.1.8.RELEASE.jar:2.1.8.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) [spring-boot-2.1.8.RELEASE.jar:2.1.8.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1204) [spring-boot-2.1.8.RELEASE.jar:2.1.8.RELEASE]
at com.cermati.googolplex.GoogolplexApplication.main(GoogolplexApplication.java:14) [classes/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.1.8.RELEASE.jar:2.1.8.RELEASE]
Caused by: java.lang.IllegalStateException: The Java/XML config for Spring MVC and Spring WebFlux cannot both be enabled, e.g. via #EnableWebMvc and #EnableWebFlux, in the same application.
at org.springframework.util.Assert.state(Assert.java:73) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.web.reactive.config.WebFluxConfigurationSupport.setApplicationContext(WebFluxConfigurationSupport.java:100) ~[spring-webflux-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.context.support.ApplicationContextAwareProcessor.invokeAwareInterfaces(ApplicationContextAwareProcessor.java:120) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.context.support.ApplicationContextAwareProcessor.postProcessBeforeInitialization(ApplicationContextAwareProcessor.java:96) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:414) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1770) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
I want to enable only Web Flux and I've added #EnableWebFlux. How to disable the Web MVC?

Answer 1

As it's not recommended to run both MVC and WebFlux in the same application, You have to set the application type to reactive or servlet using the following:
spring:
main:
web-application-type: reactive
NONE
The application should not run as a web application and should not start an embedded web server.
SERVLET
The application should run as a servlet-based web application and should start an embedded servlet web server (MVC).
REACTIVE
The application should run as a reactive web application and should start an embedded reactive web server (WebFlux).
https://docs.spring.io/spring-boot/docs/current/api/org/springframework/boot/WebApplicationType.html