title: NoSuchMethodError: org.eclipse.jetty.websocket.server.WebSocketServerFactory.<init>(Ljavax/servlet/ServletContext;)V
body: <p>I have this exception when launching my application via eclipse plugin:
  "Run as" > "GWT Development Mode with jetty"</p>
  
  <p><strong>Environment</strong>:<br>
  - GWT SDK 2.8<br>
  - spring-boot 1.5.2.RELEASE<br>
  - jetty 9.4.2<br>
  - GWT Eclipse Plugin 3.0.0  </p>
  
  <p>Context: migrate a GWT 2.6 application to GWT 2.8 and using spring-boot<br>
  application pom generated with GWT webAppCreator</p>
  
  <p><strong>Here is the stack trace</strong>:  </p>
  
  <pre><code>**Exception in thread "main" java.lang.NoSuchMethodError: 
  org.eclipse.jetty.websocket.server.WebSocketServerFactory.&lt;init&gt;(Ljavax/servlet/ServletContext;)V**
  at org.eclipse.jetty.websocket.server.NativeWebSocketConfiguration.&lt;init&gt;(NativeWebSocketConfiguration.java:53)
  at org.eclipse.jetty.websocket.server.NativeWebSocketServletContainerInitializer.getDefaultFrom(NativeWebSocketServletContainerInitializer.java:36)
  at org.eclipse.jetty.websocket.server.NativeWebSocketServletContainerInitializer.onStartup(NativeWebSocketServletContainerInitializer.java:46)
  at org.eclipse.jetty.plus.annotation.ContainerInitializer.callStartup(ContainerInitializer.java:140)
  at org.eclipse.jetty.annotations.ServletContainerInitializersStarter.doStart(ServletContainerInitializersStarter.java:63)
  at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
  at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:329)
  at org.eclipse.jetty.webapp.WebAppContext.startWebapp(WebAppContext.java:1480)
  at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1442)
  at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:799)
  at org.eclipse.jetty.servlet.ServletContextHandler.doStart(ServletContextHandler.java:261)
  at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:540)
  at com.google.gwt.dev.shell.jetty.JettyLauncher$WebAppContextWithReload.doStart(JettyLauncher.java:550)
  at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
  at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:131)
  at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:105)
  at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:113)
  at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
  at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:131)
  at org.eclipse.jetty.server.Server.start(Server.java:452)
  at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:105)
  at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:113)
  at org.eclipse.jetty.server.Server.doStart(Server.java:419)
  at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
  at com.google.gwt.dev.shell.jetty.JettyLauncher.start(JettyLauncher.java:759)
  at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:634)
  at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:923)
  at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:706)
  at com.google.gwt.dev.DevMode.main(DevMode.java:430)
  </code></pre>
  
  <p><strong>Why my application fails to start?</strong><br>
  Here is my pom and dependency tree .
  Thank you for your help</p>
  
  <p><strong>pom.xml</strong>:  </p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"&gt;
   &lt;!-- POM file generated with GWT webAppCreator --&gt;
   &lt;modelVersion&gt;4.0.0&lt;/modelVersion&gt;
   &lt;groupId&gt;com.mycompany.fonems.webapp&lt;/groupId&gt;
   &lt;artifactId&gt;Fonemswebapp&lt;/artifactId&gt;
   &lt;packaging&gt;war&lt;/packaging&gt;
   &lt;version&gt;1.0-SNAPSHOT&lt;/version&gt;
   &lt;name&gt;com.mycompany.fonems.webapp.Fonemswebapp&lt;/name&gt;
    &lt;parent&gt; &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
      &lt;artifactId&gt;spring-boot-starter-parent&lt;/artifactId&gt;
          &lt;version&gt;1.5.2.RELEASE&lt;/version&gt;
    &lt;/parent&gt;
   &lt;properties&gt;
     &lt;!-- Setting maven.compiler.source to something different to 1.8
         needs that you configure the sourceLevel in gwt-maven-plugin since
         GWT compiler 2.8 requires 1.8 (see gwt-maven-plugin block below) --&gt;
     &lt;maven.compiler.source&gt;1.8&lt;/maven.compiler.source&gt;
     &lt;maven.compiler.target&gt;1.8&lt;/maven.compiler.target&gt;
     &lt;!-- Don't let your Mac use a crazy non-standard encoding --&gt;
     &lt;project.build.sourceEncoding&gt;UTF-8&lt;/project.build.sourceEncoding&gt;
     &lt;project.reporting.outputEncoding&gt;UTF-8&lt;/project.reporting.outputEncoding&gt;
      &lt;smartgwt.version&gt;3.1&lt;/smartgwt.version&gt;
   &lt;/properties&gt;
   &lt;dependencyManagement&gt;
     &lt;dependencies&gt;
      &lt;!-- ensure all GWT deps use the same version (unless overridden) --&gt;
      &lt;dependency&gt;
        &lt;groupId&gt;com.google.gwt&lt;/groupId&gt;
        &lt;artifactId&gt;gwt&lt;/artifactId&gt;
        &lt;version&gt;2.8.0&lt;/version&gt;
        &lt;type&gt;pom&lt;/type&gt;
        &lt;scope&gt;import&lt;/scope&gt;
      &lt;/dependency&gt;
     &lt;/dependencies&gt;
   &lt;/dependencyManagement&gt;
   &lt;dependencies&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;com.mycompany.fonems&lt;/groupId&gt;
          &lt;artifactId&gt;fonems-fwk-server-common&lt;/artifactId&gt;
          &lt;version&gt;0.0.104-SNAPSHOT&lt;/version&gt;
          &lt;exclusions&gt;
              &lt;exclusion&gt;
                  &lt;artifactId&gt;xercesImpl&lt;/artifactId&gt;
                  &lt;groupId&gt;xerces&lt;/groupId&gt;
              &lt;/exclusion&gt;
          &lt;/exclusions&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;com.mycompany.fonems&lt;/groupId&gt;
          &lt;artifactId&gt;fonems-refonte-dao&lt;/artifactId&gt;
          &lt;version&gt;0.0.104-SNAPSHOT&lt;/version&gt;
          &lt;exclusions&gt;
              &lt;exclusion&gt;
                  &lt;artifactId&gt;javax.el-api&lt;/artifactId&gt;
                  &lt;groupId&gt;javax.el&lt;/groupId&gt;
              &lt;/exclusion&gt;
              &lt;exclusion&gt;
                  &lt;artifactId&gt;xercesImpl&lt;/artifactId&gt;
                  &lt;groupId&gt;xerces&lt;/groupId&gt;
              &lt;/exclusion&gt;
          &lt;/exclusions&gt;
      &lt;/dependency&gt;
     &lt;dependency&gt;
      &lt;groupId&gt;com.google.gwt&lt;/groupId&gt;
      &lt;artifactId&gt;gwt-servlet&lt;/artifactId&gt;
      &lt;scope&gt;runtime&lt;/scope&gt;
     &lt;/dependency&gt;
     &lt;dependency&gt;
      &lt;groupId&gt;com.google.gwt&lt;/groupId&gt;
      &lt;artifactId&gt;gwt-user&lt;/artifactId&gt;
      &lt;scope&gt;provided&lt;/scope&gt;
     &lt;/dependency&gt;
     &lt;dependency&gt;
      &lt;groupId&gt;com.google.gwt&lt;/groupId&gt;
      &lt;artifactId&gt;gwt-dev&lt;/artifactId&gt;
      &lt;scope&gt;provided&lt;/scope&gt;
      &lt;exclusions&gt;
          &lt;exclusion&gt;
              &lt;artifactId&gt;xercesImpl&lt;/artifactId&gt;
              &lt;groupId&gt;xerces&lt;/groupId&gt;
          &lt;/exclusion&gt;
      &lt;/exclusions&gt;
     &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;com.smartgwt&lt;/groupId&gt;
          &lt;artifactId&gt;smartgwt&lt;/artifactId&gt;
          &lt;version&gt;${smartgwt.version}&lt;/version&gt;
      &lt;/dependency&gt;
          &lt;dependency&gt;
              &lt;groupId&gt;com.smartgwt&lt;/groupId&gt;
              &lt;artifactId&gt;smartgwt-skins&lt;/artifactId&gt;
              &lt;version&gt;${smartgwt.version}&lt;/version&gt;
              &lt;optional&gt;true&lt;/optional&gt;
          &lt;/dependency&gt;
          &lt;dependency&gt;
              &lt;groupId&gt;mycompany.drh&lt;/groupId&gt;
              &lt;artifactId&gt;newncauth&lt;/artifactId&gt;
              &lt;version&gt;${mycompany.drh.version}&lt;/version&gt;
          &lt;/dependency&gt;
          &lt;dependency&gt;
              &lt;groupId&gt;mycompany.drh&lt;/groupId&gt;
              &lt;artifactId&gt;mycompany.droits-habilitations.rmi&lt;/artifactId&gt;
              &lt;version&gt;${mycompany.drh.rmi.version}&lt;/version&gt;
          &lt;/dependency&gt;
     &lt;dependency&gt;
      &lt;groupId&gt;junit&lt;/groupId&gt;
      &lt;artifactId&gt;junit&lt;/artifactId&gt;
      &lt;scope&gt;test&lt;/scope&gt;
     &lt;/dependency&gt;
          &lt;dependency&gt;
              &lt;groupId&gt;org.projectlombok&lt;/groupId&gt;
              &lt;artifactId&gt;lombok&lt;/artifactId&gt;
              &lt;scope&gt;compile&lt;/scope&gt;
          &lt;/dependency&gt;
   &lt;/dependencies&gt;
   &lt;build&gt;
     &lt;!-- Output classes directly into the webapp, so that IDEs and "mvn process-classes" update them in DevMode --&gt;
     &lt;outputDirectory&gt;${project.build.directory}/${project.build.finalName}/WEB-INF/classes&lt;/outputDirectory&gt;
     &lt;plugins&gt;
      &lt;!-- GWT Maven Plugin--&gt;
      &lt;plugin&gt;
        &lt;groupId&gt;net.ltgt.gwt.maven&lt;/groupId&gt;
        &lt;artifactId&gt;gwt-maven-plugin&lt;/artifactId&gt;
        &lt;version&gt;1.0-rc-6&lt;/version&gt;
        &lt;executions&gt;
          &lt;execution&gt;
           &lt;goals&gt;
             &lt;goal&gt;import-sources&lt;/goal&gt;
             &lt;goal&gt;compile&lt;/goal&gt;
             &lt;goal&gt;import-test-sources&lt;/goal&gt;
             &lt;goal&gt;test&lt;/goal&gt;
           &lt;/goals&gt;
          &lt;/execution&gt;
        &lt;/executions&gt;
        &lt;configuration&gt;
          &lt;moduleName&gt;com.mycompany.fonems.webapp.Fonemswebapp&lt;/moduleName&gt;
          &lt;moduleShortName&gt;Fonemswebapp&lt;/moduleShortName&gt;
          &lt;failOnError&gt;true&lt;/failOnError&gt;
          &lt;!-- GWT compiler 2.8 requires 1.8, hence define sourceLevel here if you use
              a different source language for java compilation --&gt;
          &lt;sourceLevel&gt;1.8&lt;/sourceLevel&gt;
          &lt;!-- Compiler configuration --&gt;
          &lt;compilerArgs&gt;
           &lt;!-- Ask GWT to create the Story of Your Compile (SOYC) (gwt:compile) --&gt;
           &lt;arg&gt;-compileReport&lt;/arg&gt;
           &lt;arg&gt;-XcompilerMetrics&lt;/arg&gt;
          &lt;/compilerArgs&gt;
          &lt;!-- DevMode configuration --&gt;
          &lt;warDir&gt;${project.build.directory}/${project.build.finalName}&lt;/warDir&gt;
          &lt;classpathScope&gt;compile+runtime&lt;/classpathScope&gt;
          &lt;!-- URL(s) that should be opened by DevMode (gwt:devmode). --&gt;
          &lt;startupUrls&gt;
           &lt;startupUrl&gt;Fonemswebapp.html&lt;/startupUrl&gt;
          &lt;/startupUrls&gt;
  
  &lt;!--          &lt;webappDirectory&gt;${outputFolder}&lt;/webappDirectory&gt; --&gt;
        &lt;/configuration&gt;
  
      &lt;/plugin&gt;
  
      &lt;!-- Skip normal test execution, we use gwt:test instead --&gt;
      &lt;plugin&gt;
        &lt;artifactId&gt;maven-surefire-plugin&lt;/artifactId&gt;
        &lt;version&gt;2.17&lt;/version&gt;
        &lt;configuration&gt;
          &lt;skip&gt;true&lt;/skip&gt;
        &lt;/configuration&gt;
      &lt;/plugin&gt;
     &lt;/plugins&gt;
   &lt;/build&gt;
  &lt;/project&gt;
  </code></pre>
  
  <p><strong>dependency tree</strong>:</p>
  
  <pre><code>------------------------------------------------------------------------
  Building com.mycompany.fonems.webapp.Fonemswebapp 1.0-SNAPSHOT
  ------------------------------------------------------------------------
  
  --- maven-dependency-plugin:2.10:tree (default-cli) @ Fonemswebapp ---
  com.mycompany.fonems.webapp:Fonemswebapp:war:1.0-SNAPSHOT
  +- com.mycompany.fonems:fonems-fwk-server-common:jar:0.0.104-SNAPSHOT:compile
  |  +- commons-configuration:commons-configuration:jar:1.9:compile
  |  |  \- commons-logging:commons-logging:jar:1.1.1:compile
  |  +- commons-beanutils:commons-beanutils:jar:1.9.3:compile
  |  +- org.codehaus.jackson:jackson-mapper-asl:jar:1.9.13:compile
  |  |  \- org.codehaus.jackson:jackson-core-asl:jar:1.9.13:compile
  |  +- joda-time:joda-time:jar:2.9.7:compile
  |  +- org.apache.commons:commons-lang3:jar:3.1:compile
  |  +- commons-io:commons-io:jar:2.4:compile
  |  +- commons-lang:commons-lang:jar:2.6:compile
  |  +- commons-collections:commons-collections:jar:3.2.2:compile
  |  +- org.springframework:spring-tx:jar:4.3.7.RELEASE:compile
  |  +- org.springframework:spring-context:jar:4.3.7.RELEASE:compile
  |  |  +- org.springframework:spring-aop:jar:4.3.7.RELEASE:compile
  |  |  \- org.springframework:spring-expression:jar:4.3.7.RELEASE:compile
  |  +- javax.xml.bind:jaxb-api:jar:2.2.12:compile
  |  +- javax.validation:validation-api:jar:1.1.0.Final:compile
  |  +- com.google.guava:guava:jar:18.0:compile
  |  +- commons-betwixt:commons-betwixt:jar:0.8:compile
  |  |  +- commons-beanutils:commons-beanutils-core:jar:1.7.0:compile
  |  |  \- commons-digester:commons-digester:jar:2.1:compile
  |  +- net.sf.dozer:dozer:jar:5.4.0:compile
  |  +- org.slf4j:jcl-over-slf4j:jar:1.7.24:compile
  |  +- uk.org.lidalia:sysout-over-slf4j:jar:1.0.2:compile
  |  +- org.slf4j:slf4j-api:jar:1.7.24:compile
  |  \- ch.qos.logback:logback-classic:jar:1.1.11:compile
  |    \- ch.qos.logback:logback-core:jar:1.1.11:compile
  +- com.mycompany.fonems:fonems-refonte-dao:jar:0.0.104-SNAPSHOT:compile
  |  +- com.zaxxer:HikariCP:jar:2.5.1:compile
  |  +- org.lazyluke:log4jdbc-remix:jar:0.2.7:compile
  |  +- com.mycompany.fonems:fonems-config:jar:0.0.104-SNAPSHOT:compile
  |  +- com.mycompany.fonems:fonems-refonte-model:jar:0.0.104-SNAPSHOT:compile
  |  |  +- org.jvnet.jaxb2_commons:jaxb2-basics-runtime:jar:0.6.4:compile
  |  |  +- openaccess:comFidessaInf:jar:3.0.1:compile
  |  |  +- org.springframework.boot:spring-boot-starter-validation:jar:1.5.2.RELEASE:compile
  |  |  |  +- org.springframework.boot:spring-boot-starter:jar:1.5.2.RELEASE:compile
  |  |  |  |  +- org.springframework.boot:spring-boot:jar:1.5.2.RELEASE:compile
  |  |  |  |  +- org.springframework.boot:spring-boot-autoconfigure:jar:1.5.2.RELEASE:compile
  |  |  |  |  +- org.springframework.boot:spring-boot-starter-logging:jar:1.5.2.RELEASE:compile
  |  |  |  |  |  +- org.slf4j:jul-to-slf4j:jar:1.7.24:compile
  |  |  |  |  |  \- org.slf4j:log4j-over-slf4j:jar:1.7.24:compile
  |  |  |  |  \- org.yaml:snakeyaml:jar:1.17:runtime
  |  |  |  +- org.apache.tomcat.embed:tomcat-embed-el:jar:8.5.11:compile
  |  |  |  \- org.hibernate:hibernate-validator:jar:5.3.4.Final:compile
  |  |  |    \- com.fasterxml:classmate:jar:1.3.3:compile
  |  |  \- org.springframework.boot:spring-boot-starter-data-jpa:jar:1.5.2.RELEASE:compile
  |  |    +- org.springframework.boot:spring-boot-starter-aop:jar:1.5.2.RELEASE:compile
  |  |    |  \- org.aspectj:aspectjweaver:jar:1.8.9:compile
  |  |    +- org.springframework.boot:spring-boot-starter-jdbc:jar:1.5.2.RELEASE:compile
  |  |    +- org.hibernate:hibernate-core:jar:5.0.12.Final:compile
  |  |    |  +- antlr:antlr:jar:2.7.7:compile
  |  |    |  \- org.jboss:jandex:jar:2.0.0.Final:compile
  |  |    +- org.springframework.data:spring-data-jpa:jar:1.11.1.RELEASE:compile
  |  |    |  +- org.springframework.data:spring-data-commons:jar:1.13.1.RELEASE:compile
  |  |    |  \- org.springframework:spring-orm:jar:4.3.7.RELEASE:compile
  |  |    \- org.springframework:spring-aspects:jar:4.3.7.RELEASE:compile
  |  +- org.springframework:spring-core:jar:4.3.7.RELEASE:compile
  |  +- org.springframework:spring-test:jar:4.3.7.RELEASE:compile
  |  +- org.springframework:spring-jdbc:jar:4.3.7.RELEASE:compile
  |  +- org.springframework:spring-beans:jar:4.3.7.RELEASE:compile
  |  +- org.hsqldb:hsqldb:jar:2.3.3:compile
  |  +- commons-dbcp:commons-dbcp:jar:1.4:compile
  |  |  \- commons-pool:commons-pool:jar:1.6:compile
  |  +- com.oracle:ojdbc7:jar:12.1.0.2:compile
  |  \- de.jpdigital:hibernate5-ddl-maven-plugin:jar:1.0.0:compile
  |    +- org.apache.maven:maven-artifact:jar:3.3.9:compile
  |    +- org.apache.maven:maven-core:jar:3.3.9:compile
  |    |  +- org.apache.maven:maven-model:jar:3.3.9:compile
  |    |  +- org.apache.maven:maven-settings:jar:3.3.9:compile
  |    |  +- org.apache.maven:maven-settings-builder:jar:3.3.9:compile
  |    |  |  \- org.apache.maven:maven-builder-support:jar:3.3.9:compile
  |    |  +- org.apache.maven:maven-repository-metadata:jar:3.3.9:compile
  |    |  +- org.apache.maven:maven-model-builder:jar:3.3.9:compile
  |    |  +- org.apache.maven:maven-aether-provider:jar:3.3.9:compile
  |    |  |  \- org.eclipse.aether:aether-spi:jar:1.0.2.v20150114:compile
  |    |  +- org.eclipse.aether:aether-impl:jar:1.0.2.v20150114:compile
  |    |  +- org.eclipse.aether:aether-api:jar:1.0.2.v20150114:compile
  |    |  +- org.eclipse.aether:aether-util:jar:1.0.2.v20150114:compile
  |    |  +- org.eclipse.sisu:org.eclipse.sisu.plexus:jar:0.3.2:compile
  |    |  |  +- javax.enterprise:cdi-api:jar:1.0:compile
  |    |  |  |  \- javax.annotation:jsr250-api:jar:1.0:compile
  |    |  |  \- org.eclipse.sisu:org.eclipse.sisu.inject:jar:0.3.2:compile
  |    |  +- com.google.inject:guice:jar:no_aop:4.0:compile
  |    |  |  +- javax.inject:javax.inject:jar:1:compile
  |    |  |  \- aopalliance:aopalliance:jar:1.0:compile
  |    |  +- org.codehaus.plexus:plexus-interpolation:jar:1.21:compile
  |    |  +- org.codehaus.plexus:plexus-classworlds:jar:2.5.2:compile
  |    |  +- org.codehaus.plexus:plexus-component-annotations:jar:1.6:compile
  |    |  \- org.sonatype.plexus:plexus-sec-dispatcher:jar:1.3:compile
  |    |    \- org.sonatype.plexus:plexus-cipher:jar:1.4:compile
  |    +- org.apache.maven:maven-plugin-api:jar:3.3.9:compile
  |    +- org.apache.maven:maven-project:jar:3.0-alpha-2:compile
  |    |  +- org.apache.maven:maven-compat:jar:3.0-alpha-2:compile
  |    |  |  \- org.apache.maven.wagon:wagon-provider-api:jar:1.0-beta-4:compile
  |    |  +- org.codehaus.plexus:plexus-container-default:jar:1.0-beta-3.0.5:compile
  |    |  |  +- org.apache.xbean:xbean-reflect:jar:3.4:compile
  |    |  |  |  +- log4j:log4j:jar:1.2.12:compile
  |    |  |  |  \- commons-logging:commons-logging-api:jar:1.1:compile
  |    |  |  \- com.google.code.google-collections:google-collect:jar:snapshot-20080530:compile
  |    |  +- org.codehaus.woodstox:wstx-asl:jar:3.2.6:compile
  |    |  |  \- stax:stax-api:jar:1.0.1:compile
  |    |  +- org.sonatype.spice:model-builder:jar:1.3:compile
  |    |  \- org.apache.maven:maven-project-builder:jar:3.0-alpha-2:compile
  |    +- org.codehaus.plexus:plexus-utils:jar:3.0.24:compile
  |    +- org.hibernate:hibernate-entitymanager:jar:5.0.12.Final:compile
  |    |  +- org.jboss.logging:jboss-logging:jar:3.3.0.Final:compile
  |    |  +- dom4j:dom4j:jar:1.6.1:compile
  |    |  +- org.hibernate.common:hibernate-commons-annotations:jar:5.0.1.Final:compile
  |    |  +- org.hibernate.javax.persistence:hibernate-jpa-2.1-api:jar:1.0.0.Final:compile
  |    |  +- org.javassist:javassist:jar:3.21.0-GA:compile
  |    |  \- org.apache.geronimo.specs:geronimo-jta_1.1_spec:jar:1.1.1:compile
  |    +- org.hibernate:hibernate-envers:jar:5.0.12.Final:compile
  |    +- org.reflections:reflections:jar:0.9.10:compile
  |    |  \- com.google.code.findbugs:annotations:jar:2.0.1:compile
  |    \- javax.transaction:javax.transaction-api:jar:1.2:compile
  +- com.google.gwt:gwt-servlet:jar:2.8.0:runtime
  +- com.google.gwt:gwt-user:jar:2.8.0:provided
  |  +- com.google.jsinterop:jsinterop-annotations:jar:1.0.1:provided
  |  +- com.google.jsinterop:jsinterop-annotations:jar:sources:1.0.1:provided
  |  +- javax.validation:validation-api:jar:sources:1.0.0.GA:provided
  |  +- javax.servlet:javax.servlet-api:jar:3.1.0:provided
  |  \- org.w3c.css:sac:jar:1.3:provided
  +- com.google.gwt:gwt-dev:jar:2.8.0:provided
  |  +- com.google.code.gson:gson:jar:2.8.0:provided
  |  +- org.ow2.asm:asm:jar:5.0.3:provided
  |  +- org.ow2.asm:asm-util:jar:5.0.3:provided
  |  |  \- org.ow2.asm:asm-tree:jar:5.0.3:provided
  |  +- org.ow2.asm:asm-commons:jar:5.0.3:provided
  |  +- colt:colt:jar:1.2.0:provided
  |  +- ant:ant:jar:1.6.5:provided
  |  +- com.ibm.icu:icu4j:jar:50.1.1:provided
  |  +- tapestry:tapestry:jar:4.0.2:provided
  |  +- net.sourceforge.htmlunit:htmlunit:jar:2.21:provided
  |  |  +- xalan:xalan:jar:2.7.2:provided
  |  |  |  \- xalan:serializer:jar:2.7.2:provided
  |  |  +- org.apache.httpcomponents:httpclient:jar:4.5.3:provided
  |  |  |  \- org.apache.httpcomponents:httpcore:jar:4.4.6:provided
  |  |  +- org.apache.httpcomponents:httpmime:jar:4.5.3:provided
  |  |  +- commons-codec:commons-codec:jar:1.10:provided
  |  |  +- net.sourceforge.htmlunit:htmlunit-core-js:jar:2.17:provided
  |  |  +- net.sourceforge.htmlunit:neko-htmlunit:jar:2.21:provided
  |  |  +- net.sourceforge.cssparser:cssparser:jar:0.9.18:provided
  |  |  \- org.eclipse.jetty.websocket:websocket-client:jar:9.4.2.v20170220:provided
  |  |    +- org.eclipse.jetty:jetty-client:jar:9.4.2.v20170220:provided
  |  |    \- org.eclipse.jetty.websocket:websocket-common:jar:9.2.14.v20151106:provided
  |  |       \- org.eclipse.jetty.websocket:websocket-api:jar:9.2.14.v20151106:provided
  |  +- org.eclipse.jetty:jetty-webapp:jar:9.4.2.v20170220:provided
  |  |  +- org.eclipse.jetty:jetty-xml:jar:9.4.2.v20170220:provided
  |  |  \- org.eclipse.jetty:jetty-servlet:jar:9.4.2.v20170220:provided
  |  |    \- org.eclipse.jetty:jetty-security:jar:9.4.2.v20170220:provided
  |  |       \- org.eclipse.jetty:jetty-server:jar:9.4.2.v20170220:provided
  |  +- org.eclipse.jetty:jetty-servlets:jar:9.4.2.v20170220:provided
  |  |  +- org.eclipse.jetty:jetty-continuation:jar:9.4.2.v20170220:provided
  |  |  +- org.eclipse.jetty:jetty-http:jar:9.4.2.v20170220:provided
  |  |  +- org.eclipse.jetty:jetty-util:jar:9.4.2.v20170220:provided
  |  |  \- org.eclipse.jetty:jetty-io:jar:9.4.2.v20170220:provided
  |  +- org.eclipse.jetty:jetty-annotations:jar:9.4.2.v20170220:provided
  |  |  +- org.eclipse.jetty:jetty-plus:jar:9.4.2.v20170220:provided
  |  |  |  \- org.eclipse.jetty:jetty-jndi:jar:9.2.14.v20151106:provided
  |  |  \- javax.annotation:javax.annotation-api:jar:1.2:provided
  |  \- org.eclipse.jetty:apache-jsp:jar:9.4.2.v20170220:provided
  |    +- org.eclipse.jetty.toolchain:jetty-schemas:jar:3.1:provided
  |    +- org.mortbay.jasper:apache-jsp:jar:8.5.9.1:provided
  |    |  \- org.mortbay.jasper:apache-el:jar:8.0.33:provided
  |    \- org.eclipse.jdt.core.compiler:ecj:jar:4.4.2:provided
  +- com.smartgwt:smartgwt:jar:3.1:compile
  +- com.smartgwt:smartgwt-skins:jar:3.1:compile
  +- mycompany.drh:newncauth:jar:2.0.0:compile
  +- mycompany.drh:mycompany.droits-habilitations.rmi:jar:02.10.01:compile
  +- junit:junit:jar:4.12:test
  |  \- org.hamcrest:hamcrest-core:jar:1.3:test
  \- org.projectlombok:lombok:jar:1.16.14:compile
  ------------------------------------------------------------------------
  BUILD SUCCESS
  </code></pre>
  
  <h2>    ------------------------------------------------------------------------</h2>
  
  <p>I tested the solutions proposed by Andy, but not successful, always the same exception<br>
  <strong>test 1 proposed by Andy (add property jetty.version 9.2.14.v20151106)</strong>    </p>
  
  <p><strong>pom  modification</strong>:<br>
  +1 line  </p>
  
  <pre><code>&lt;properties&gt;
    &lt;jetty.version&gt;9.2.14.v20151106&lt;/jetty.version&gt; 
  &lt;/properties&gt;
  </code></pre>
  
  <p><strong>dependency tree modifications</strong> (other lines are unchanged compared to the first tree dependency):  </p>
  
  <pre><code>+- com.google.gwt:gwt-dev:jar:2.8.0:provided
  |  +- com.google.code.gson:gson:jar:2.8.0:provided
  |  +- org.ow2.asm:asm:jar:5.0.3:provided
  |  +- org.ow2.asm:asm-util:jar:5.0.3:provided
  |  |  \- org.ow2.asm:asm-tree:jar:5.0.3:provided
  |  +- org.ow2.asm:asm-commons:jar:5.0.3:provided
  |  +- colt:colt:jar:1.2.0:provided
  |  +- ant:ant:jar:1.6.5:provided
  |  +- com.ibm.icu:icu4j:jar:50.1.1:provided
  |  +- tapestry:tapestry:jar:4.0.2:provided
  |  +- net.sourceforge.htmlunit:htmlunit:jar:2.21:provided
  |  |  +- xalan:xalan:jar:2.7.2:provided
  |  |  |  \- xalan:serializer:jar:2.7.2:provided
  |  |  +- org.apache.httpcomponents:httpclient:jar:4.5.3:provided
  |  |  |  \- org.apache.httpcomponents:httpcore:jar:4.4.6:provided
  |  |  +- org.apache.httpcomponents:httpmime:jar:4.5.3:provided
  |  |  +- commons-codec:commons-codec:jar:1.10:provided
  |  |  +- net.sourceforge.htmlunit:htmlunit-core-js:jar:2.17:provided
  |  |  +- net.sourceforge.htmlunit:neko-htmlunit:jar:2.21:provided
  |  |  +- net.sourceforge.cssparser:cssparser:jar:0.9.18:provided
  |  |  \- org.eclipse.jetty.websocket:websocket-client:jar:9.2.14.v20151106:provided
  |  |    \- org.eclipse.jetty.websocket:websocket-common:jar:9.2.14.v20151106:provided
  |  |       \- org.eclipse.jetty.websocket:websocket-api:jar:9.2.14.v20151106:provided
  |  +- org.eclipse.jetty:jetty-webapp:jar:9.2.14.v20151106:provided
  |  |  +- org.eclipse.jetty:jetty-xml:jar:9.2.14.v20151106:provided
  |  |  \- org.eclipse.jetty:jetty-servlet:jar:9.2.14.v20151106:provided
  |  |    \- org.eclipse.jetty:jetty-security:jar:9.2.14.v20151106:provided
  |  +- org.eclipse.jetty:jetty-servlets:jar:9.2.14.v20151106:provided
  |  |  +- org.eclipse.jetty:jetty-continuation:jar:9.2.14.v20151106:provided
  |  |  +- org.eclipse.jetty:jetty-http:jar:9.2.14.v20151106:provided
  |  |  +- org.eclipse.jetty:jetty-util:jar:9.2.14.v20151106:provided
  |  |  \- org.eclipse.jetty:jetty-io:jar:9.2.14.v20151106:provided
  |  +- org.eclipse.jetty:jetty-annotations:jar:9.2.14.v20151106:provided
  |  |  +- org.eclipse.jetty:jetty-plus:jar:9.2.14.v20151106:provided
  |  |  |  \- org.eclipse.jetty:jetty-jndi:jar:9.2.14.v20151106:provided
  |  |  \- javax.annotation:javax.annotation-api:jar:1.2:provided
  |  \- org.eclipse.jetty:apache-jsp:jar:9.2.14.v20151106:provided
  |    +- org.eclipse.jetty:jetty-server:jar:9.2.14.v20151106:provided
  |    +- org.eclipse.jetty.toolchain:jetty-schemas:jar:3.1.M0:provided
  |    \- org.mortbay.jasper:apache-jsp:jar:8.0.9.M3:provided
  |       \- org.mortbay.jasper:apache-el:jar:8.0.33:provided
  +- com.smartgwt:smartgwt:jar:3.1:compile
  +- com.smartgwt:smartgwt-skins:jar:3.1:compile
  </code></pre>
  
  <hr>
  
  <p><strong>test 2 proposed by Andy (force dependencies in 9.2.14 to 9.4.2.v20170220)</strong>  </p>
  
  <p><strong>pom modifications</strong>:  </p>
  
  <pre><code> &lt;dependencyManagement&gt;
    &lt;dependency&gt;
        &lt;groupId&gt;org.eclipse.jetty.websocket&lt;/groupId&gt;
        &lt;artifactId&gt;websocket-common&lt;/artifactId&gt;
        &lt;version&gt;9.4.2.v20170220&lt;/version&gt;
        &lt;scope&gt;provided&lt;/scope&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
        &lt;groupId&gt;org.eclipse.jetty.websocket&lt;/groupId&gt;
        &lt;artifactId&gt;websocket-api&lt;/artifactId&gt;
        &lt;version&gt;9.4.2.v20170220&lt;/version&gt;
        &lt;scope&gt;provided&lt;/scope&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
        &lt;groupId&gt;org.eclipse.jetty&lt;/groupId&gt;
        &lt;artifactId&gt;jetty-jndi&lt;/artifactId&gt;
        &lt;version&gt;9.4.2.v20170220&lt;/version&gt;
        &lt;scope&gt;provided&lt;/scope&gt;
      &lt;/dependency&gt;
     &lt;/dependencies&gt;
   &lt;/dependencyManagement&gt;
  </code></pre>
  
  <p><strong>dependency tree modifications</strong> (other lines are unchanged compared to the first tree dependency):  </p>
  
  <pre><code>+- com.google.gwt:gwt-user:jar:2.8.0:provided
  ... 
  |  |    \- org.eclipse.jetty.websocket:websocket-common:jar:9.4.2.v20170220:provided
  |  |       \- org.eclipse.jetty.websocket:websocket-api:jar:9.4.2.v20170220:provided
  ...
  |  |  |  \- org.eclipse.jetty:jetty-jndi:jar:9.4.2.v20170220:provided
  </code></pre>
  
  <p><strong>last test logs</strong>:  </p>
  
  <pre><code>11:17:35,004 |-INFO in ch.qos.logback.classic.joran.action.ConfigurationAction - debug attribute not set
  11:17:35,020 |-INFO in ch.qos.logback.classic.joran.action.ConfigurationAction - Will scan for changes in [file:/C:/Dev/Appli/fonems-webapp/fonemswebapp/src/mai
  n/webapp/WEB-INF/classes/logback.xml] 
  11:17:35,020 |-INFO in ch.qos.logback.classic.joran.action.ConfigurationAction - Setting ReconfigureOnChangeTask scanning period to 1 minutes
  11:17:35,020 |-ERROR in ch.qos.logback.core.joran.spi.Interpreter@2:52 - RuntimeException in Action for tag [configuration] java.lang.NullPointerException
  
  at java.lang.NullPointerException
  at java.lang.ClassLoader.resolveClass0(Native Method)
  at java.lang.ClassLoader.resolveClass(ClassLoader.java:964)
  at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:523)
  at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
  at ch.qos.logback.classic.util.EnvUtil.isGroovyAvailable(EnvUtil.java:36)
  at ch.qos.logback.classic.joran.action.ConfigurationAction.begin(ConfigurationAction.java:68)
  at ch.qos.logback.core.joran.spi.Interpreter.callBeginAction(Interpreter.java:269)
  at ch.qos.logback.core.joran.spi.Interpreter.startElement(Interpreter.java:145)
  at ch.qos.logback.core.joran.spi.Interpreter.startElement(Interpreter.java:128)
  at ch.qos.logback.core.joran.spi.EventPlayer.play(EventPlayer.java:50)
  at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:165)
  at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:152)
  at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:110)
  ...
  at com.google.gwt.dev.DevMode.main(DevMode.java:430)
  11:17:35,020 |-INFO in ch.qos.logback.classic.joran.JoranConfigurator@6af1c1b - Registering current configuration as safe fallback point
  
  SLF4J: Actual binding is of type [ch.qos.logback.classic.util.ContextSelectorStaticBinder]
  Exception in thread "main" java.lang.NoSuchMethodError: org.eclipse.jetty.websocket.server.WebSocketServerFactory.&lt;init&gt;(Ljavax/servlet/ServletContext;)V
  at org.eclipse.jetty.websocket.server.NativeWebSocketConfiguration.&lt;init&gt;(NativeWebSocketConfiguration.java:53)  
  </code></pre>
  
  <h2>    ------------------------------------------------------------------------</h2>
  
  <p><strong>I did an other test</strong>: I delete spring-boot dependency: result=same exception. Moreover, the dependency tree shows all jetty atrifacts in version 9.2.14.v20151106</p>
  
  <p>Moreover, I try to search the class <code>org.eclipse.jetty.websocket.server.WebSocketServerFactory</code> in jars but not found. Where is it present? Why this class is mentionned in logs?<br>
  Thank you for your help</p>