嵌入式Jetty服务器不适用于Java Vaadin应用程序

Question

I am building a vaadin app with maven that will use an embedded jetty server to run. I have found a couple examples online and have done my best to integrate what I learned from them into my code, but it is not working.

I have made an EmbeddedJetty class:

import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.ServletContextHandler;
import com.wndgroup.auction.supportsystem.DashboardServlet;

public class EmbeddedJetty {
    public static void main(String[] args) throws Exception {
        Server server = new Server(8080);
        ServletContextHandler handler = new ServletContextHandler(server, "/example");
        handler.addServlet(DashboardServlet.class, "/");
        server.start();
    }
}

And this is my DashboardServlet class:

import javax.servlet.ServletException;
import com.vaadin.server.VaadinServlet;

@SuppressWarnings("serial")
public class DashboardServlet extends VaadinServlet {

    @Override
    protected final void servletInitialized() throws ServletException {
        super.servletInitialized();
        getService().addSessionInitListener(new DashboardSessionInitListener());
    }
}

When I try to run the EmbeddedJetty class, I get back this stack trace:

Exception in thread "main" java.lang.NoClassDefFoundError: org/eclipse/jetty/util/component/ContainerLifeCycle
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:455)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:367)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:455)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:367)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:455)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:367)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:455)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:367)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at com.wndgroup.auction.supportsystem.EmbeddedJetty.main(EmbeddedJetty.java:10)
Caused by: java.lang.ClassNotFoundException: org.eclipse.jetty.util.component.ContainerLifeCycle
    at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 49 more

And here is the new stack trace I am getting after importing the jetty-util jar :

Nov 18, 2015 1:31:58 PM org.eclipse.jetty.util.log.Log initialized
INFO: Logging initialized @225ms
Nov 18, 2015 1:31:58 PM org.eclipse.jetty.server.Server doStart
INFO: jetty-9.2.2.v20140723
Nov 18, 2015 1:31:58 PM org.eclipse.jetty.server.handler.ContextHandler doStart
INFO: Started o.e.j.s.ServletContextHandler@35bbe5e8{/example,null,AVAILABLE}
Nov 18, 2015 1:31:58 PM org.eclipse.jetty.server.AbstractConnector doStart
INFO: Started ServerConnector@880ec60{HTTP/1.1}{0.0.0.0:8080}
Nov 18, 2015 1:31:58 PM org.eclipse.jetty.util.component.AbstractLifeCycle setFailed
WARNING: FAILED org.eclipse.jetty.server.Server@3f3afe78: java.lang.NoClassDefFoundError: org/eclipse/jetty/util/Uptime
java.lang.NoClassDefFoundError: org/eclipse/jetty/util/Uptime
    at org.eclipse.jetty.server.Server.doStart(Server.java:379)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at com.wndgroup.auction.supportsystem.EmbeddedJetty.main(EmbeddedJetty.java:13)
Caused by: java.lang.ClassNotFoundException: org.eclipse.jetty.util.Uptime
    at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 3 more

Exception in thread "main" java.lang.NoClassDefFoundError: org/eclipse/jetty/util/Uptime
    at org.eclipse.jetty.server.Server.doStart(Server.java:379)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at com.wndgroup.auction.supportsystem.EmbeddedJetty.main(EmbeddedJetty.java:13)
Caused by: java.lang.ClassNotFoundException: org.eclipse.jetty.util.Uptime
    at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 3 more

I am extremely new to Jetty and Vaadin so any help would be much appreciated!

Answer 1

Don't add arbitrary jars to your project, that will never work.

Use a build tool, (really, can't emphasis this enough!) You have many to choose from.

• Maven
• Gradle
• Ant + Ivy
• Scala/SBT
• Buildr
• etc ...

What's going on is that you have multiple versions of jetty present in your classpath.

I see 9.2.2.v20140723 in your startup logs (version is discovered from different places) and references to org.eclipse.jetty.util.Uptime which wasn't introduced until 9.2.6.v20141203 .

The Uptime class is an in internal class, for a bug fix related to java8 compact3 and android compatibility .

However you also have a Server object that is attempting to use this class, which means you have a version of jetty-server.jar at a version after 9.2.6.v20141203 , but a jetty-util.jar at a version before it.

What you need to do:

1. Use a build tool!
2. Eliminate shot-in-the-dark arbitrary artifact references from your build/runtime.
3. From your EmbeddedJetty.java example, you only need a reference to the jetty-servlet-${version}.jar (that's it. don't reference anything else, see step #4)
4. let the artifact dependency knowledge do its thing, the build tool will pull in the rest of the artifacts that you need, automatically, and sanely.
5. If you are using the jetty-all.jar artifact, quit using it in your project (that's not what that artifact exists for) .