Question

How to sort a list of objects for duplicates in java?basically that every object should be uniqe in list after sorting. Maybe someone knows a good example.

Answer 1

You can add the elements of the List to a Set, and then create a new List with those elements, like this:

List<Object> originalList = new ArrayList<Object>();
// the elements of originalList get added here

Set<Object> set = new HashSet<Object>(originalList);
List<Object> newList = new ArrayList<Object>(set);

Be aware that:

• I’m using Object as the type for the List and Set, replace it with the appropriate type to suit your needs
• For the above to work correctly, the objects in the list must override both hashCode and equals
• The elements in the new list will be in different order from those in the original list