Eclipse webapp project does not start properly on Tomcat anymore after a PC restart

Question

I had a web app configured and running when I shut down my PC. Then when I started it strange things started to happen: I use eclipse indigo ee. It gave me a class not found

Answer 1

Apparently the environment is dirty. I'd suggest to clean and rebuild all.

1. Remove project from Tomcat (rightclick Tomcat, Add/Remove project, remove project)
2. Close project in Eclipse (rightclick project, Close)
3. Clean Tomcat (rightclick Tomcat, Clean)
4. Reopen project in Eclipse (rightclick project, Open)
5. Clean project in Eclipse (Project > Clean... > Clean selected projects below, select project)
6. Add project to Tomcat (rightclick Tomcat, Add/Remove projects, add project)
7. Start Tomcat (rightclick Tomcat, Start).

It isn't possible to pinpoint a real cause for this problem, there are too many possible factors. For example, the workspace wasn't properly shutdown, or Tomcat wasn't properly shutdown, or you did "too many" things simultaneously which caused race conditions in background tasks of Eclipse, etcetera. This is not explicitly related to Eclipse+Tomcat combination. This happens to my experience also so now and then with JBoss AS and Glassfish servers.