import java.util.Enumeration;
import java.util.Hashtable;

/*
 * Example of keys() method.
 */
public class HashtableExample
{
    public static void main( String[] args )
    {

        Hashtable<String, String> hashtable = new Hashtable<String, String>();

        /*
         * Key = CountryCode,Value = CountryName.
         */
        hashtable.put("AF", "AFGHANISTAN");
        hashtable.put("BE", "BELGIUM");
        hashtable.put("US", "UNITED STATES");
        hashtable.put("IN", "INDIA");

        System.out.println("hashtable : " + hashtable + "\n");

        /*
         * Returns an enumeration of the keys in this hashtable.
         */
        Enumeration<String> enumeration = hashtable.keys();

        
        System.out.println("key");
        System.out.println("-----");
        
        /*
         * Tests if this enumeration contains more elements.
         */
        while( enumeration.hasMoreElements() )
        {
            /*
             * Returns the next element of this enumeration if this enumeration
             * object has at least one more element to provide.
             */
            String key = enumeration.nextElement();
            System.out.println(key);

        }

    }
}