Tomcat: Unresolved compilation problems: The import javax.servlet.Servlet cannot be resolved

During my tests with servlets I got a really confusing error message. After restarting Tomcat I tried to execute the servlet

and got the following screen:

Tomcat Servlet Problem
Tomcat Servlet Problem

I was confused, because the servlet-api.jar was included in the lib folder. To be sure, you can display the loaded classes by -verbose:class swicth.

Fix: Recompile your class in your eclipse environment. There seems to be a  problem which leads sometimes to non proper compilations in eclipse.I was wondering about that, but I found some other blogs / boards where other people faced the same behavior.