Learn Java for Android Development, Third Edition

Exploring Sorted Maps

TreeMap is an example of a sorted map, which is a map that maintains its entries in ascending order, sorted according to the keys’ natural ordering or according to a comparator that is supplied when the sorted map is created. Sorted maps are described by the SortedMap interface.

SortedMap (whose generic type is SortedMap<K, V>) extends Map. With two exceptions, the methods it inherits from Map behave identically on sorted maps as on other maps:

• The Iterator instance returned by the iterator() method on any of the sorted map’s Collection views traverses the collections in order.
• The arrays returned by the Collection views’ toArray() methods contain the keys, values, or entries in order.

Note  Although not guaranteed, ...