Remove Duplicates in Java

Description:
You have an ArrayList with duplicates, and you need to remove them

Solution:

• Create a HashSet with the ArrayList as the constructor argument:
  
  

  HashSet hashSet = new HashSet(myArrayList);

• If the order is important, use a LinkedHashSet:
  
  

  LinkedHashSet  linkedHashSet = new LinkedHashSet(myArrayList);

• Use the following method to remove duplcates:
  

  static ArrayList deDupKeepingFirst(ArrayList withDups,
    Comparator comparator,boolean presorted) {
   if (!presorted) {
    Collections.sort(withDups, comparator);
   }
   int size = withDups.size();
  
   ArrayList result = new ArrayList(size);
   if (size <= 1) {
    if (size == 1) {
     result.add(withDups.get(0));
    }
    return result;
   }
   Object prev = withDups.get(0);
   result.add(prev);
  
   for (int i = 1; i < size; i++) {
    Object o = withDups.get(i);
    if (comparator.compare(o, prev) != 0) {
     result.add(o);
     prev = o;
    }
    else
     System.out.println(o.toString());
   }
   return result;
  }
  
  private static class StringComp implements Comparator
  {
   public int compare(Object o1, Object o2)
   {
    return o1.toString().compareToIgnoreCase((o2).toString());
   }
  }