Retrieving the Ends for a TreeSet : TreeSet « Collections « Java Tutorial

You can use the first() and last() methods of TreeSet to get the elements at the ends of the tree:

public Object first()
public Object last()

The first() element is the one that is ordered first in the set, while last() is last.

A NoSuchElementException will be thrown by either method if there are no elements in the set.

import java.util.Arrays;
import java.util.Set;
import java.util.TreeSet;

public class MainClass {
  public static void main(String args[]) throws Exception {
    String elements[] = { "A", "C", "D", "G", "F" };
    TreeSet set = new TreeSet(Arrays.asList(elements));
[A, C, D, F, G]

9.22.1.TreeSet Class
9.22.2.Creating a TreeSet
9.22.3.Get Synchronized Set from TreeSet
9.22.4.Copy all elements in TreeSet to an Object Array
9.22.5.Get Head Set from Java TreeSet
9.22.6.Get lowest and highest value stored in TreeSet
9.22.7.Get Size of TreeSet
9.22.8.Get Sub Set from TreeSet
9.22.9.Get Tail Set from TreeSet
9.22.10.Iterate through elements of TreeSet
9.22.11.Check if a particular value exists in TreeSet
9.22.12.Remove specified element from TreeSet
9.22.13.Remove all elements from TreeSet
9.22.14.The second two constructors are copy constructors
9.22.15.Sort items in a Set
9.22.16.To add a single element: the add() method: public boolean add(Object element)
9.22.17.Retrieving the Ends for a TreeSet
9.22.18.Fetching Elements: the iterator() method: public Iterator iterator()
9.22.19.Working with Subsets
9.22.20.The third method subSet() provides the end points: public SortedSet subSet(Object fromElement, Object toElement)
9.22.21.headset, tailset and subset
9.22.22.Viewing Subsets
9.22.23.Looping through a sorted set backwards