public void removeAllDuplicates()
   {
       String train = " ";
       int i = 1;
       train = train + words.get(0) + " ";
       while(i<words.size()){
           String test = " " + words.get(i) + " ";
           if(train.contains(test)){
               words.remove(i);
           }
           else
           {
               train = train + words.get(i) + " ";
               i++;
           }
       }
   }