※ 引述《uopsdod (pcman)》之铭言：
: Given:
: enum Exaplme {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 java.utilHash.Map; instead, the
: programmer must use a java.util.EnumMap.
: d. The Example values can be used in a java.tuil.SortedSet, but the set will
: NOT be sorted because enumerated types do NOT implement java.lang.Comparable
:

感谢。 本来以为enum会重在内部自己新定义 < 算子。

java没有operator overloading，唯一较特别的只有string +

感谢大家 了解了!

唯“二”比较特别的是String 的 + 和+= :P