The following stacktrace is what I get when i try to access a servlet, which seems running fine from Tomcat manager.
11 Sep, 2012 11:50:12 AM org.apache.catalin
Go to the Project Properties -> Deployment Assembly -> Check whether the maven dependencies are visible, if they are missing the also we get the same error. I could resolve my adding the maven dependency into the Deployment Assembly.
[After adding Maven dependency into the Deployment Assembly, it seems like this]
https://i.stack.imgur.com/7iwaW.jpg