Difference in order between HashSet and ArrayList

Sun Oct 21, 2012 1:10 pm

Difference in order between HashSet and ArrayList for a group of strings objects :

Code:: import java.util.ArrayList; import java.util.HashSet; import java.util.Iterator; import java.util.List; import java.util.Set; public class Main { public static void main(String[] args) { String stringsArr[] = {"adam", "tom", "ali", "mina", "saly"}; List arraylist = new ArrayList(); Set hashSet = new HashSet(); for (String str : stringsArr) { arraylist.add(str); hashSet.add(str); } Iterator listIterator = arraylist.iterator(); Iterator setIterator = hashSet.iterator(); System.out.println("Iterations for array list"); while (listIterator.hasNext()) { System.out.print(listIterator.next() + "\t"); } /* * Notice that the output of set object is not in order. * */ System.out.println("\nIterations for hash set."); while (setIterator.hasNext()) { System.out.print(setIterator.next() + "\t"); } } }

The output for this snippet :

Code:: Iterations for array list. adam tom ali mina saly Iterations for hash set. saly ali adam mina tom