一个关于Java中SortedMap定义的问题
在SortedMap接口的解释中有这么一段话：
* <p>Note that the ordering maintained by a sorted map (whether or not an
* explicit comparator is provided) must be <i>consistent with equals</i> if
* the sorted map is to correctly implement the <tt>Map</tt> interface. (See
* the <tt>Comparable</tt> interface or <tt>Comparator</tt> interface for a
* precise definition of <i>consistent with equals</i>.) This is so because
* the <tt>Map</tt> interface is defined in terms of the <tt>equals</tt>
* operation, but a sorted map performs all key comparisons using its
* <tt>compareTo</tt> (or <tt>compare</tt>) method, so two keys that are
* deemed equal by this method are, from the standpoint of the sorted map,
* equal. The behavior of a tree map <i>is</i> well-defined even if its
* ordering is inconsistent with equals; it just fails to obey the general
* contract of the <tt>Map</tt> interface.请问这段话是什么意思？
就是要求map里面的对象，做compareTo和equals来比较的时候结果是一致的。比如compareTo返回0，那么equal一定是true。但有的对象可不是这样的，比如BigDecimal