Spring Boot Websockets in Wildfly

Question

Hi I need to deploy my Spring Boot app into Wildfly 8.1 and I\'m getting the following exception:

Caused by: java.lang.RuntimeException: java.lang.Cl

Answer 1

I'm not sure, but your POM around websockets should be like this:

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

<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-websocket</artifactId>
    <scope>provided</scope>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-tomcat</artifactId>
    <scope>provided</scope>
</dependency>

spring-messaging, spring-websocket, jackson-databind, spring-boot-starter-web are redundant.

There is also spring-boot-starter-thymeleaf.

However I think the root of your cause is tomcat-embed-websocket.

Answer 2

For me , spring-boot-starter-websocket and spring-boot-starter-web by default includes the spring-boot-starter-tomcat so exclude the tomcat, like below without version of spring boot:

<dependency>  
        <groupId>org.springframework.boot</groupId>  
        <artifactId>spring-boot-starter-web</artifactId>  
        <exclusions>
            <exclusion>
                <groupId>org.apache.tomcat.embed</groupId>
                <artifactId>tomcat-embed-websocket</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-websocket</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-tomcat</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

Answer 3

spring-boot-starter-web and spring-boot-starter-websocket by default includes the spring-boot-starter-tomcat so exclude the tomcat, like below

     <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <version>${spring-boot.version}</version>
        <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-websocket</artifactId>
        <version>${spring-boot.version}</version>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-tomcat</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

and include undertow, make sure the tomcat exists no where in the classpath.

Answer 4

You need exclude tomcat-embed-websocket

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.apache.tomcat.embed</groupId>
                <artifactId>tomcat-embed-websocket</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

Answer 5

Use the following command to find all dependencies that includes spring-boot-starter-tomcat:

mvn dependency:tree -Dincludes=org.springframework.boot:spring-boot-starter-tomcat

Exclude Tomcat starter from all your dependencies listed by this command.

After that, you might need to add javax.servlet-api as a provided dependency:

<dependency>
    <artifactId>javax.servlet</artifactId>
    <groupId>javax.servlet-api</groupId>
    <scope>provided</scope>
</dependency>

Gradle users with this issue: check out the comments on this ticket: https://github.com/spring-projects/spring-boot/issues/6166