TreeSet.headSet(E toElement) has the following syntax.
public SortedSet <E> headSet(E toElement)
In the following code shows how to use TreeSet.headSet(E toElement) method.
//from w w w . java 2s . c o m import java.util.Iterator; import java.util.TreeSet; public class Main { public static void main(String[] args) { TreeSet <Integer> tree = new TreeSet<Integer> (); tree.add(12); tree.add(13); tree.add(14); tree.add(15); tree.add(16); tree.add(17); // getting values less than 15 TreeSet<Integer> treeheadset = (TreeSet)tree.headSet(15); Iterator<Integer> iterator = treeheadset.iterator(); while (iterator.hasNext()){ System.out.println(iterator.next()); } } }
The code above generates the following result.