java.util · java.base · since Java 1.2

SortedMap

declaration

public interface SortedMap<K, V> extends Map<K, V>

A Map that keeps its keys in ascending order, by natural ordering or a Comparator. Adds endpoint and range operations over Map.

Key methods

`K firstKey() / lastKey()`	Lowest / highest key (throws if empty).
`SortedMap<K, V> headMap(K to) / tailMap(K from)`	Range views over the key ordering.
`SortedMap<K, V> subMap(K from, K to)`	Half-open [from, to) key-range view.
`Comparator<? super K> comparator()`	The key ordering, or null for natural order.