Using HashMap to store number of words import java.util.*; public class HashMapTest { private static String names[] = { "one", "two", "three", "four", "five", "six", "seven", "two", "ten", "four" }; public HashMapTest() { HashMap m = new HashMap(); Integer i; for ( int k = 0; k < names.length; k++ ) { i = ( Integer ) m.get( new Character( names[ k ].charAt( 0 ) ) ); // if key is not in map then give it value one // otherwise increment its value by 1 if ( i == null ) m.put( new Character( names[ k ].charAt( 0 ) ), new Integer( 1 ) ); else m.put( new Character( names[ k ].charAt( 0 ) ), new Integer( i.intValue() + 1 ) ); } System.out.println( "\nnumber of words beginning with " + "each letter: " ); printMap( m ); } public void printMap( Map mapRef ) { System.out.println( mapRef.toString() ); System.out.println( "size: " + mapRef.size() ); System.out.println( "isEmpty: " + mapRef.isEmpty() ); } public static void main( String args[] ) { new HashMapTest(); } }