Source 598 clean up

Summary:
Change non static accesses to static members using declaring type
Change indirect accesses to static members to direct accesses (accesses through subtypes)
Remove unused imports
Add missing '@Override' annotations
Add missing '@Override' annotations to implementations of interface methods
Add missing '@Deprecated' annotations
Remove unnecessary casts
Remove unnecessary '$NON-NLS$' tags



DIFF:
https://pastebin.com/3Ei8PWSv

Was used and commited in 599. Thanks a lot.