Tomcat 6+: Infamous "SEVERE: Error listenerStart" message - How-To debug this error?

I’m sure if you have been developing with Java and Tomcat for sometime, you are likely to run into the infamous debug error. SEVERE: Error listenerStart You will most likely start Googling it trying to find out what the heck is going on. And in trying to see the extended logging on what that “listenerStart” error means. After some lucky searches, you will see links asking you to drop a “log4j.

Maven - GWT - Vaadin - including additional custom jars in a maven project under "\web-inf\lib"

With a lot of folks trying Google Web Toolkit (GWT) and\or Vaadin (combined with Maven), one of the problems that they might encounter is this: How do I get my custom Vaadin themes or GWT jar files included under my "\web-inf\lib" folder inside the war Here’s a link to the such a question in detail. The answer is a lot simpler than you think. But before we explore the answer, I should warn you that this approach is going away from what Maven would like you to do.

GWT and Spring Integration - is a restricted class

When trying to integrate both Spring and GWT, one might encounter the following error in the Spring Eclipse IDE: “ is a restricted class”. The problem happens when you try to use Spring configuration for your database. In my case, I was using Spring to update data back to a H2 database. Well, here’s one way to deal with this issue. Disable the “Google App Engine”. Yes, based on my research, if you’re using GWT, you can disable Google App Engine and still continue your development with GWT.