Towards cleaner nesting

'Everything about nesting in Java is a mess. The terminology is a mess (top level classes, nested classes, inner classes, local classes, anonymous classes); the set of restrictions on what can nest in what is ad-hoc (can have local classes but not local interfaces; inner classes cannot have static members, including static nested classes), and the set of rules about what must be, can be, or cannot be static is also ad-hoc (nested classes can be static or not, nested interfaces are