SanityCheck
Hello world! (0-args, no closure)
ABCD Hello world! (4-args, no closure)
Caught NPE
(BoxUnbox) Hello boxing world! (0-args, no closure)
(BoxUnbox) Boxing repeatedly yields referentially-equal objects
(BoxUnbox) Caught NPE for unbox-lambda
(BoxUnbox) Caught NPE for box-lambda
(BoxUnbox) Caught ClassCastException for unbox-lambda