1. Once connected to the desktop, launch Eclipse.
2. Right click on the project that is failing and select Build Path -> Configure Build Path…
3. Click on the Libraries tab and click Add External Jars.
4. You should see a prompt showing you a directory containing a file called servlet-api-2.5.jar (if not navigate to /usr/share/maven-repo/javax/servlet/servlet-api/2.5/). Click on this file and click OK.
5. Click OK again to close all pop-ups. Then with the same project still highlighted in the project explorer, in the eclipse menu click Project -> Clean.
6. Click OK to accept all the default options, which should clean the project and rebuild it.
7. At this point, if you know of any other projects that are not working correctly with the Tomcat server, repeat steps 1-6 for that project now, before continuing.
8. Now you have to re-add the projects to the Tomcat server. Click on the Servers tab in the bottom right pane.
9. Right click the Tomcat server and select Add and Remove…
10. In this popup, remove all the projects that you just rebuilt (or you can just select Remove All) then click Finish.
11. Reopen the popup by right clicking the Tomcat server and selecting Add and Remove…
12. Add back the projects previously removed (or you can just select Add All) and then click Finish.
13. Finally, start (or restart) the Tomcat server.
You should now be able to access the projects from the Firefox web browser.