ClassNotFoundException (Apache CXF Webservices)

I am trying to run a webservice that I coded in Apache CXF. I keep getting this error:

Stacktrace:] with root cause
java.lang.ClassNotFoundException: org.apache.cxf.message.Message
    at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:351)

I have the cxf-core artifact added to my pom file and also I can see it included in the WAR file. And also the JAR which is actually throwing the exception. The part of the code that is throwing the exception is:

getBindingProvider().getRequestContext().put(BindingProviderProperties.CONNECT_TIMEOUT, connectTimeout);
    getBindingProvider().getRequestContext().put(BindingProvider.ENDPOINT_ADDRESS_PROPERTY, endPointUrl);
    getBindingProvider().getRequestContext().put("com.sun.xml.internal.ws.request.timeout", 3720000);

    Map<String, List<String>> headers = new HashMap<String, List<String>>();

    headers.put("Content-Type", Collections.singletonList("application/soap+xml"));
    headers.put(Message.CONTENT_TRANSFER_ENCODING, Collections.singletonList("UTF-8"));
    headers.put(Message.ENCODING, Collections.singletonList("UTF-8"));

    getBindingProvider().getRequestContext().put(MessageContext.HTTP_REQUEST_HEADERS, headers);

Am I doing something wrong?

I am building it with the maven-jar-plugin, like so:

<plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <inherited>true</inherited>
            <configuration>
                <archive>
                    <manifest>
                        <addClasspath>true</addClasspath>
                        <addDefaultEntries>true</addDefaultEntries>
                        <addBuildEnvironmentEntries>true</addBuildEnvironmentEntries>
                        <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
                        <addDefaultSpecificationEntries>true</addDefaultSpecificationEntries>
                        <classpathPrefix>lib/</classpathPrefix>
                    </manifest>
                </archive>
                <attachClasses>true</attachClasses>
                <includeEmptyDirectories>true</includeEmptyDirectories>
                <outputDirectory>${project.basedir}/target/</outputDirectory>
            </configuration>
        </plugin>

How are you running it? If you run the war file, which contains the cxf jar file, which contains the Message class, it should not throw a classcastexception. Unless you have conflicting dependencies. Or something goes wrong with classloaders.

Check for conflicting jars. In intellij, they are marked at the right of your screen. Eclipse has something similar.