title: How to resolve java.lang.NoClassDefFoundError?
body: <p>I'm currently working on a simple web project, for which I am using the SDK of <a href="http://www.polarion.com/" rel="nofollow">Polarion</a>. When trying to work with the according *.jar-Files, Tomcat 7 throws the following error message on start-up:</p>
  
  <pre><code>SCHWERWIEGEND: Exception sending context initialized event to listener instance of class org.apache.myfaces.webapp.StartupServletContextListener
  java.lang.NoClassDefFoundError: Lcom/polarion/alm/ws/client/session/SessionWebService;
  </code></pre>
  
  <p>According to the research I have undertaken, Java is trying to find an <em>instance</em> of com.polarion.ws.client.session.SessionWebService (thus the leading <em>L</em>). I have checked the classpath for the needed entry - it's there.</p>
  
  <pre><code>C:\Polarion\polarion\SDK\lib\com.polarion.alm.ws.client\wsclient.jar
  </code></pre>
  
  <p>As of now, I've run out of ideas what could have gone wrong. Do you have any ideas?</p>
  
  <p>Thanks a lot!
  Simon</p>