Java – find unique entries in the list

List<Object> listObj = new ArrayList<Object[]>();

List<Object> listObj = new ArrayList<Object[]>();
listObj.add(new Object[]{1,"abc",new Date(21/1/2001)});
listObj.add(new Object[]{1,new Date(21/1/2001)});
listObj.add(new Object[]{2,"acc",new Date(21/1/2001)});
Set<Object[]> unique = new HashSet<Object[]>();
unique.addAll();

I look forward to:

{1,abc,21/1/2001},{2,acc,21/1/2001}

Instead, I get:

{1,{1,(21/1/2001},21/1/2001}

How do I find a unique entry in this example?

Solution

Arrays in java do not have the concept of equality that allows them to work You need to define a custom class with numbers, strings, and dates, and implement equals / hashcode yourself to allow it to work