Spring boot 2: JettyServletWebServerFactory handler leads to IllegalStateException: No ServletContext set - spring-boot

Question

I am trying to customize my jetty and there is no issue with connectors however when the handler is added the except is appeared
The config has the following view:
import org.eclipse.jetty.server.handler.DefaultHandler
#Configuration
class JettyConfig {
#Bean
fun jettyServer(): JettyServletWebServerFactory {
val factory = JettyServletWebServerFactory(8080)
factory.addServerCustomizers(JettyServerCustomizer { server ->
server.connectors = getJettyConnectors(server)
server.handler = DefaultHandler() // if this row exclude the problem disappes
})
return factory
}
the pom.xml I have these dependencies:
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.4.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-autoconfigure</artifactId>
</dependency>
The stack trace of the exception
Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-08-06 15:26:39.863 [main] ERROR o.s.boot.SpringApplication - Application run failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'resourceHandlerMapping' defined in class path resource [org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.HandlerMapping]: Factory method 'resourceHandlerMapping' threw exception; nested exception is java.lang.IllegalStateException: No ServletContext set
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:590)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1256)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1105)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:503)
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:760)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:869)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550)
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:762)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:398)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:330)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1258)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246)
at com.my.AppKt.main(App.kt:123)
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.HandlerMapping]: Factory method 'resourceHandlerMapping' threw exception; nested exception is java.lang.IllegalStateException: No ServletContext set
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:582)
... 18 common frames omitted
Caused by: java.lang.IllegalStateException: No ServletContext set
at org.springframework.util.Assert.state(Assert.java:73)
at org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport.resourceHandlerMapping(WebMvcConfigurationSupport.java:483)
at org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$EnableWebMvcConfiguration$$EnhancerBySpringCGLIB$$39999424.CGLIB$resourceHandlerMapping$38(<generated>)
at org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$EnableWebMvcConfiguration$$EnhancerBySpringCGLIB$$39999424$$FastClassBySpringCGLIB$$f0700681.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:361)
at org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$EnableWebMvcConfiguration$$EnhancerBySpringCGLIB$$39999424.resourceHandlerMapping(<generated>)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
... 19 common frames omitted
I create my app in the Kotlin but I don't think it may be a cause of error because currently application work with spring core and we don't have any issue but after migration to srping-boot the promblem appears

Answer 1

server.handler = DefaultHandler()
That means you have no handlers that do anything of note.
You essentially have a server that will always report 404 and tells you that you have no contexts.
You'll need, at a minimum, a ServletContextHandler (the handler type that provides a ServletContext for you), which I believe spring-boot creates for you, if there is no handler declared.
If you need something more complex, see https://stackoverflow.com/a/39217143/775715 for more details on Handler fundamentals (including how to create a tree of handlers)