I checked out a project from CVS into Eclipse. Apparently Eclipse does not treat this as a Java project even though it is. So, whenever I typed something in the editor followed by a "." (for example, "System."), a window will appear with the following message:
This compilation unit is not on the build path of a Java project.
Also, since Eclipse does not treat this as a Java project, it does not do auto build and other stuff like code completions etc.
What can I do to get Eclipse to treat it as a Java project?
Make sure that you didn't check in the .project file (or delete it from CVS). Remove the project from the workspace.
Check it out again, using the option with the three dots (...) at the end. Eclipse should now notice that it isn't configured for Eclipse and show you a wizard to do so. Don't click "finish", but "next", until you come to the page where you can configure the project nature. Make it a java project. Voila.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus