$ javac  src/SequencedCollectionsDemo.java && java  SequencedCollectionsDemo     (21.0.12.1)
getFirst/getLast: a c
reversed view   : [c, b, a]
addFirst+removeLast: [z, a, b]
LinkedHashSet reversed: [3, 2, 1]
firstEntry/lastEntry : x=1 z=3
putFirst        : {w=0, x=1, y=2, z=3}
reversed map    : {z=3, y=2, x=1, w=0}
view sees add   : [3, 2, 1]
immutable list : UnsupportedOperationException
HashSet         : no getFirst (unordered)