There is a bug in Tomcat, WO or Project Wonder that causes problems if you have more than one webapp deployed in a single instance of Tomcat if they don't all have identical classpaths. This bug will not impact most developers. If you are deploying a single application, or all your applications share the same classpath, then you will not run into this bug. Full description is here.
WO developers have been able to deploy their applications as a WAR bundle in a J2EE container since WO 5.1, and as an independent SSDD (Servlet Single Directory Deployment) bundles and WAR files since WO 5.2. This article guides you through the simple setup in WOLips to allow you to deploy you application to a servlet container such as Apache Tomcat.