ClassCastException with Spring-Websocket because of Tomcat ServerContainer - spring

Question

While trying to connect to Spring Websocket with SockJS, I am getting an error
org.springframework.web.util.NestedServletException: Request processing failed;
nested exception is org.springframework.web.socket.sockjs.SockJsException:
Uncaught failure in SockJS request, uri=http://localhost:8083//subscribe/info/771/nay07fet/websocket;
nested exception is org.springframework.web.socket.sockjs.SockJsTransportFailureException:
WebSocket handshake failure; nested exception is java.lang.ClassCastException:
org.eclipse.jetty.websocket.jsr356.server.ServerContainer cannot be cast
to org.apache.tomcat.websocket.server.WsServerContainer
From online I figured out that I shall disable Tomcat in Classpath to overcome it, but no matter how I try, I can not get rid of Tomcat.
How I can reliably exclude tomcat from any project? Note that I found it in several places.
My current Dependency tree is here: http://pastebin.com/pH1iQejd
and it contains some tomcat. I need to get rid of everything that might cause that type confusion.
Here's my gradle.build (I tried some exlcudes but without success):
group 'com.company'
if (!hasProperty("buildNumber")) {
version "1.0.0-SNAPSHOT"
} else {
version "1.0.${buildNumber}-SNAPSHOT"
}
buildscript {
repositories {
mavenCentral()
maven {
url "https://plugins.gradle.org/m2"
}
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:1.3.3.RELEASE")
classpath("gradle.plugin.com.boxfuse.client:flyway-release:4.0.1")
classpath fileTree(dir: 'libs', include: '*.jar')
classpath fileTree(dir: 'src/main/resources/db/migration', include: '*.sql')
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'spring-boot'
sourceCompatibility = 1.8
targetCompatibility = 1.8
repositories {
mavenCentral()
maven {
url "https://plugins.gradle.org/m2"
}
}
dependencies {
// tag::jetty[]
compile("org.springframework.boot:spring-boot-starter-web") {
exclude module: "spring-boot-starter-tomcat"
exclude module: 'spring-boot-starter-logging'
}
compile("org.springframework.boot:spring-boot-starter-jetty") {
exclude module: "spring-boot-starter-tomcat"
exclude module: 'spring-boot-starter-logging'
}
// end::jetty[]
// tag::actuator[]
compile("org.springframework.boot:spring-boot-starter-actuator")
compile("org.springframework.boot:spring-boot-starter-data-jpa"){
exclude module: "spring-boot-starter-tomcat"
exclude module: 'spring-boot-starter-logging'
}
compile("org.springframework.boot:spring-boot-starter-data-rest")
compile("org.springframework.boot:spring-boot-starter-websocket")
// http://mvnrepository.com/artifact/org.springframework.security/spring-security-core
compile group: 'org.springframework.security', name: 'spring-security-core', version: '4.1.0.RELEASE'
compile group: 'ch.qos.logback', name: 'logback-classic', version: '1.+'
compile group: 'com.google.code.gson', name: 'gson', version: '2.5'
compile group: 'com.rabbitmq', name: 'amqp-client', version: '3.5.6'
compile group: 'commons-configuration', name: 'commons-configuration', version: '1.9'
compile group: 'com.google.guava', name: 'guava', version: '18.0'
compile group: 'org.apache.logging.log4j', name: 'log4j-api', version: '2.5'
compile group: 'org.apache.logging.log4j', name: 'log4j-core', version: '2.5'
compile("org.springframework:spring-messaging")
compile 'org.springframework.amqp:spring-rabbit:1.5.5.RELEASE'
compile("com.h2database:h2")
compile 'org.quartz-scheduler:quartz:2.2.1'
compile group: 'joda-time', name: 'joda-time', version: '2.3'
//compile("com.npspot:jtransit-light:1.0.6")
compile("io.fastjson:boon:0.33")
compile fileTree(dir: 'libs', include: '*.jar')
// end::actuator[]
testCompile group: 'junit', name: 'junit', version: '4.11'
testCompile("org.springframework.boot:spring-boot-starter-test")
}
configurations {
compile.exclude module: "spring-boot-starter-tomcat"
compile.exclude module: 'spring-boot-starter-logging'
runtime.exclude module: "spring-boot-starter-tomcat"
runtime.exclude module: 'spring-boot-starter-logging'
}
test {
reports {
junitXml.enabled = true
html.enabled = false
}
}
springBoot {
executable = true
}

Answer 1

I was facing this problem as well. I solved it by adding the exclude clause to the websocket dependency, i.e.:
compile("org.springframework.boot:spring-boot-starter-websocket") {
exclude module: "spring-boot-starter-tomcat"
}
After this, I realized it wasn't necessary to have the exclusion on all the other ones; it's only necessary on starter-web and starter-websocket.