Iterate through keys of Java Hashtable example

/*
  Iterate through keys of Java Hashtable example
  This Java Example shows how to iterate through the keys contained in the
  Hashtable object.
*/
 
import java.util.Hashtable;
import java.util.Enumeration;
 
public class IterateThroughKeysOfHashtableExample {
 
  public static void main(String[] args) {
 
    //create Hashtable object
    Hashtable ht = new Hashtable();
 
    //add key value pairs to Hashtable
    ht.put("1","One");
    ht.put("2","Two");
    ht.put("3","Three");
 
    /*
      get Enumeration of keys contained in Hashtable using
      Enumeration keys() method of Hashtable class
    */
    Enumeration e = ht.keys();
 
    //iterate through Hashtable keys Enumeration
    while(e.hasMoreElements())
      System.out.println(e.nextElement());
  }
}
 
/*
Output would be
3
2
1
*/