Problem: you get an error during build saying “Build error java.util.Enumeration cannot be resolved” even though you have the correct import statement.
Solution: Set the compiler compliance level to 1.4 (window->preferences->Java->compiler) and rebuild.

Problem: The error “project .jetemitters is missing required library” prevents you from building your project.
Solution: Go to package explorer window and click the down arrow button in the right hand corner.

Then select filter and uncheck *.resources. The project .jetemitters should now show up. Just delete it.