試題詳解

       enum Example{ONE, TWO, THREE} 

Which statement is true?
(A) The expressions (ONE == ONE) and ONE .equals(ONE) are both guaranteed to be true.
(B) The expression (ONE ＜ TWO) is guaranteed to be true and ONE.compareTo(TWO) is guaranteed to be less than one.
(C) The Example values cannot be used in a raw javautil.HashMap； instead, the programmer must use a java.util.EnumMap.
(D) The Example values can be used in a java.util.SortedSet, but the set will NOT be sorted because enumerated types do NOT implement java.lang.Comparable.