hashmaps lists sums to

import java.util.HashMap;
import java.util.HashSet;
import java.util.Set;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.Map;

class start
{
  private int desiredSum;
  HashMap <Integer,Integer> subset;
  HashMap <Integer,ArrayList<Integer>> valueIndices;

  start()
  {
    super();
    desiredSum = 9;
    int integers[] = { -4, 8, 6, -4, 3, 6 };
    System.out.println( "Looking for sums to " + desiredSum );
    System.out.println( "Originally " + display( integers ));
    mapValuesToIndexes( integers );
    displayIndices( valueIndices );
    for( int i=0; i<integers.length; i++ )
    {
      int searchTarget = desiredSum - integers[i];
      if( valueIndices.containsKey( searchTarget ) )
      {
        ArrayList<Integer> indices = valueIndices.get( searchTarget );
        System.out.println(
         "[" + i + "]=" + integers[i] + " + "
         + searchTarget + "=" + indices.toString() );
      }
    }

  }
  public static void main( String args[])
  {
    start s = new start();
  }

  private static String display( int a[] )
  {
    StringBuilder strb = new StringBuilder();
    String newline = System.getProperty( "line.separator" );
    for( int i=0; i<a.length; i++ )
    {
      strb.append( a[i] + "," );
    }
    strb.append( newline );
    return strb.toString();
  }
  private void mapValuesToIndexes( int a[] )
  {
    int index;
    int value;
    valueIndices = new HashMap <Integer,ArrayList<Integer>> ();
    for( int i=0; i<a.length; i++ )
    {
      index = i;
      value = a[i];
      if( valueIndices.containsKey( value ) )
      {
        ArrayList<Integer> indices = valueIndices.get( value );
        indices.add( index );
        System.out.println( " duplicate value " + a[i] );
      }else
      {
        ArrayList<Integer> indices = new ArrayList<Integer>();
        indices.add( index );
        valueIndices.put( value , indices );
      }
    }
  }

  private void displayIndices( HashMap <Integer,ArrayList<Integer>> valueIndices )
  {
 //   for( ArrayList<Integer> alist : valueIndices.values() )
    Set <Map.Entry <Integer, ArrayList<Integer>> > s = valueIndices.entrySet();
    Iterator <Map.Entry <Integer, ArrayList<Integer>> > it = s.iterator();
    while( it.hasNext() )
    {
      Map.Entry <Integer, ArrayList<Integer>> mapEntry = it.next();
      int value = mapEntry.getKey();
      ArrayList<Integer> indices = mapEntry.getValue();
      System.out.println( " value " + value + " size " + indices.size() + "=" + indices.toString() );
    }
  }

} //end class