Summary: Add checksum verification.
Reviewed-by: iklam, dholmes, mschoene

Reviewed-by: chegar, alanb

Reviewed-by: bae, serb

Reviewed-by: mullan
Contributed-by: NBradford Wetmore <bradford.wetmore@oracle.com>

Reviewed-by: ahgross

8053938: Collections.checkedList(empty list).replaceAll((UnaryOperator)null) doesn't throw NPE after JDK-8047795
Reviewed-by: rriggs, mduigou

Reviewed-by: valeriep

Reviewed-by: coffeys

Reviewed-by: valeriep

8049418: [macosx] PopupMenuListener.popupMenuWillBecomeVisible is not called for empty combobox on MacOS/aqua look and feel
Reviewed-by: anthony, pchelko

Reviewed-by: alanb