Weird NoClassDef-s with Eclipse Jetty's Maven plugin

Question

I am using an embedded Jetty via the Eclipse Jetty Maven plugin (9.1.0.M0).

I have the following plugin configuration in my pom.xml:

                <plugin>
                    <groupId>org.eclipse.jetty</groupId>
                    <artifactId>jetty-maven-plugin</artifactId>
                    <version>${version.jetty}</version>

                    <configuration>
                        <scanIntervalSeconds>10</scanIntervalSeconds>
                        <daemon>true</daemon>

                        <webApp>
                            <contextPath>/</contextPath>
                            <descriptor>${basedir}/src/test/webapp/WEB-INF/web.xml</descriptor>
                        </webApp>

                        <httpConnector>
                            <port>48080</port>
                        </httpConnector>

                        <stopPort>19081</stopPort>
                        <stopKey>53AS9DS1FD8E3WEFEW9GR1ER8G2ER0WE31</stopKey>
                    </configuration>

                    <executions>
                        <execution>
                            <id>jetty-start</id>

                            <phase>test-compile</phase>
                            <goals>
                                <goal>run</goal>
                            </goals>
                        </execution>
                        <execution>
                            <id>jetty-stop</id>

                            <phase>test</phase>
                            <goals>
                                <goal>stop</goal>
                            </goals>
                        </execution>
                    </executions>
                </plugin>

I keep getting the following exception when Jetty is shutting down:

2013-09-27 04:51:08.309:WARN:oejuc.AbstractLifeCycle:Thread-68: FAILED WebSocketClient@873794597{FAILED,8<=8<=200,i=8,q=0}: java.lang.NoClassDefFoundError: org/eclipse/jetty/util/thread/QueuedThreadPool$1
java.lang.NoClassDefFoundError: org/eclipse/jetty/util/thread/QueuedThreadPool$1
    at org.eclipse.jetty.util.thread.QueuedThreadPool.doStop(QueuedThreadPool.java:121)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:90)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.stop(ContainerLifeCycle.java:129)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.doStop(ContainerLifeCycle.java:148)
    at org.eclipse.jetty.websocket.client.WebSocketClient.doStop(WebSocketClient.java:263)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:90)
    at org.eclipse.jetty.util.thread.ShutdownThread.run(ShutdownThread.java:133)
Caused by: 
java.lang.ClassNotFoundException: org.eclipse.jetty.util.thread.QueuedThreadPool$1
    at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:50)
    at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:244)
    at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.doStop(QueuedThreadPool.java:121)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:90)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.stop(ContainerLifeCycle.java:129)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.doStop(ContainerLifeCycle.java:148)
    at org.eclipse.jetty.websocket.client.WebSocketClient.doStop(WebSocketClient.java:263)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:90)
    at org.eclipse.jetty.util.thread.ShutdownThread.run(ShutdownThread.java:133)
2013-09-27 04:51:08.310:WARN:oejuc.AbstractLifeCycle:Thread-68: FAILED org.eclipse.jetty.websocket.client.WebSocketClient@34150c25: java.lang.NoClassDefFoundError: org/eclipse/jetty/util/thread/QueuedThreadPool$1
java.lang.NoClassDefFoundError: org/eclipse/jetty/util/thread/QueuedThreadPool$1
    at org.eclipse.jetty.util.thread.QueuedThreadPool.doStop(QueuedThreadPool.java:121)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:90)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.stop(ContainerLifeCycle.java:129)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.doStop(ContainerLifeCycle.java:148)
    at org.eclipse.jetty.websocket.client.WebSocketClient.doStop(WebSocketClient.java:263)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:90)
    at org.eclipse.jetty.util.thread.ShutdownThread.run(ShutdownThread.java:133)
Caused by: 
java.lang.ClassNotFoundException: org.eclipse.jetty.util.thread.QueuedThreadPool$1
    at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:50)
    at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:244)
    at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.doStop(QueuedThreadPool.java:121)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:90)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.stop(ContainerLifeCycle.java:129)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.doStop(ContainerLifeCycle.java:148)
    at org.eclipse.jetty.websocket.client.WebSocketClient.doStop(WebSocketClient.java:263)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:90)
    at org.eclipse.jetty.util.thread.ShutdownThread.run(ShutdownThread.java:133)
Exception in thread "Thread-68" java.lang.NoClassDefFoundError: org/eclipse/jetty/util/thread/QueuedThreadPool$1
    at org.eclipse.jetty.util.thread.QueuedThreadPool.doStop(QueuedThreadPool.java:121)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:90)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.stop(ContainerLifeCycle.java:129)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.doStop(ContainerLifeCycle.java:148)
    at org.eclipse.jetty.websocket.client.WebSocketClient.doStop(WebSocketClient.java:263)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:90)
    at org.eclipse.jetty.util.thread.ShutdownThread.run(ShutdownThread.java:133)
Caused by: java.lang.ClassNotFoundException: org.eclipse.jetty.util.thread.QueuedThreadPool$1
    at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:50)
    at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:244)
    at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
    ... 7 more

I have tried adding jetty-util as a dependency of the plugin, (and, also -- the project). This didn't help and it's driving me mad. While the build is indeed passing, I really can't stand seeing these errors when Jetty is shutting down at the end of my Maven build.

Please, advise! Many thanks in advance!

Answer 1

I would suggest you use a release version, e.g. 9.0.5.v20130815, instead of milestone ( which is still in development ) as you're using right now 9.1.0.M0