Okay -- on second thought I'd go with a static `getInstance` method which returns a new `HiddenSubredditManager` (not a cached singleton). The contents of the preference should be loaded at the point when the `HiddenSubredditManager` is created. This should avoid anything having to be stored statically.

On an unrelated note, I'd change the name of `showSubreddit` to `isSubredditHidden` to avoid confusion.