Exclude packages from Eclipse's organize imports

Question

There are certain classes, such as Closeable, File and Container, that have doppelgänger classes in obscure packages that I am extreme

Answer 1

I don't see, for example, the com.sun.*.Closeable in your example when I use ContentAssist or Organize Imports. I think where you want to configure it is in Preferences > Java > Appearance > Type Filters. However, I don't have com.sun.* listed in my filter list. Maybe it's the "Hide forbidden references" option.