=== List (ArrayList implements SequencedCollection) ===
getFirst()  = alpha
getLast()   = gamma
after addLast("delta"): [alpha, beta, gamma, delta]
reversed()  = [delta, gamma, beta, alpha]

=== Deque (ArrayDeque implements SequencedCollection) ===
getFirst()  = 1
getLast()   = 3
reversed()  = [3, 2, 1]

=== LinkedHashSet implements SequencedSet (insertion order preserved) ===
getFirst()  = red
getLast()   = blue
reversed()  = [blue, green, red]

=== LinkedHashMap implements SequencedMap (insertion order) ===
firstEntry() = jan=1
lastEntry()  = mar=3
after putFirst("dec", 12): {dec=12, jan=1, feb=2, mar=3}
sequencedKeySet() = [dec, jan, feb, mar]
reversed()         = {mar=3, feb=2, jan=1, dec=12}

=== TreeMap implements SequencedMap too (order = comparator order, not insertion) ===
tree contents (natural order) = {1=one, 2=two, 3=three}
firstEntry() = 1=one
lastEntry()  = 3=three
reversed()   = {3=three, 2=two, 1=one}
