title: jetty:run causes class not found exception for org.mortbay.jetty.webapp.WebAppContext
body: <p>Hi i have the following configuration. </p>
  
  <pre><code>&lt;plugin&gt;
      &lt;groupId&gt;org.mortbay.jetty&lt;/groupId&gt;
      &lt;artifactId&gt;jetty-maven-plugin&lt;/artifactId&gt;
      &lt;version&gt;8.1.3.v20120416&lt;/version&gt;
  &lt;/plugin&gt;
  </code></pre>
  
  <p>and in my jetty-env.xml I have </p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;!DOCTYPE Configure PUBLIC "-//Mort Bay Consulting//DTD Configure//EN" "http://www.eclipse.org/jetty/configure.dtd"&gt;
  &lt;Configure class="org.mortbay.jetty.webapp.WebAppContext"&gt;
  &lt;/Configure&gt;
  </code></pre>
  
  <p>When i run with mvn jetty:run i get the following error. </p>
  
  <pre><code>Caused by: java.lang.ClassNotFoundException: org.mortbay.jetty.webapp.WebAppCont
  ext
          at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
          at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
          at java.security.AccessController.doPrivileged(Native Method)
          at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
          at org.eclipse.jetty.util.Loader.loadClass(Loader.java:92)
          at org.eclipse.jetty.xml.XmlConfiguration$JettyXmlConfiguration.nodeClas
  s(XmlConfiguration.java:349)
          at org.eclipse.jetty.xml.XmlConfiguration$JettyXmlConfiguration.configur
  e(XmlConfiguration.java:314)
          at org.eclipse.jetty.xml.XmlConfiguration.configure(XmlConfiguration.jav
  a:279)
          at org.mortbay.jetty.plugin.AbstractJettyMojo.applyJettyXml(AbstractJett
  yMojo.java:449)
          at org.mortbay.jetty.plugin.AbstractJettyMojo.startJetty(AbstractJettyMo
  jo.java:467)
  </code></pre>
  
  <p>How do i fix this? </p>