NavigableMap.headMap(K toKey) has the following syntax.
SortedMap < K , V > headMap(K toKey)
In the following code shows how to use NavigableMap.headMap(K toKey) method.
/*ww w . j av a 2 s. c o m*/ import java.util.NavigableMap; import java.util.TreeMap; public class Main { public static void main(String[] args) { NavigableMap<Integer, String> map = new TreeMap<Integer, String>(); map.put(2, "two"); map.put(1, "one"); map.put(3, "three"); System.out.println( map.headMap(1) + "\n"); } }
The code above generates the following result.