I am running Eclipse Galileo on Ubuntu 10.04 LTS. Ubuntu crashed on me today, and after rebooting, I found that Eclipse has completely lost the Java Perspective (it's like the perspective and all associated views never existed) and the .metadata dir in my workspace is empty except for version.ini.
What's up with that? Why did it happen? How can I prevent it? How can I recover from it?
First I would try to create a new workspace, and see whether there are the missing elements present. If the other workspace is working correctly, then your original workspace got corrupted.
You can import all projects to the new workspace, and try to use it (although this way you may lose the global settings, that are stored in your old workspace, but at least all your projects and project-specific settings are intact).
On the other hand, if the new workspace also does not work, then you could try launching eclipse with the -clean parameter, or uninstalling and reinstalling it.