Example:
Set s=new TreeSet();
s.add("leandro");
s.add("jose");
s.add("pedro");
s.add("carlos");
s.add("alex");
Iterator i=s.iterator();
while(i.hasNext()){
System.out.println(i.next());
}
this will print all the elements in the natural order, I added
string elements, String class implements java.lang.Comparable, if your object does not implements Comparable, you can create a Comparator, just implementing java.util.Comparator. Hope it helps!