Hashtable keys Iterator example

Ilias TsagklisNovember 11th, 2012Last Updated: May 25th, 2013

0 66 1 minute read

In this example we shall show you how to obtain a Hashtable keys Iterator, that is an iterator of the keys of the Hashtable. To obtain a Hashtable keys Iterator one should perform the following steps:

Create a new Hashtable.
Populate the hashtable with elements, using put(K key, V value) API method of Hashtable.
Invoke keys() API method of Hashtable. It returns an Enumeration of the keys contained in the Hashtable.
Iterate through the enumeration, with hasMoreElements() and nextElement() API method of Enumeration,

as described in the code snippet below.

package com.javacodegeeks.snippets.core;
 
import java.util.Hashtable;
import java.util.Enumeration;
 
public class HashtableKeysIterator {
 
  public static void main(String[] args) {
 
    // Create a Hashtable and populate it with elements
    Hashtable hashtable = new Hashtable();
    hashtable.put("key_1","value_1");
    hashtable.put("key_2","value_2");
    hashtable.put("key_3","value_3");
 
    // Enumeration keys() operation returns an Enumeration of keys contained in Hashtable
    Enumeration keysEnumeration = hashtable.keys();
 
    // Iterate through Hashtable keys Enumeration
    System.out.println("Hashtable keys : ");
    while(keysEnumeration.hasMoreElements())

System.out.println(keysEnumeration.nextElement());
  }
}

Output: