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Tag: hashset

Add unique elements in HashSet based on attributes of framework provided non-editable object classes

I am trying to generate a HashSet containing unique Employee instances. Uniqueness should be established based on the object properties. The problem is that I end up with having duplicates. Note that Employee class is provided by a framework, and it’s not possible to provide custom implementations for equals() and hashCode(). Employee class: This would result in a Set mapped

What is the purpose of placing a HashSet inside of a HashMap?

For example: private HashMap<Integer, HashSet> variableName; I understand that HashMap implements Map and doesn’t allow duplicate keys and HashSet implements Set and doesn’t allow for duplicate values, but what is the purpose of placing a HashSet inside of a HashMap? Do they not achieve similar tasks by themselves (though in different ways and with different performance)? What functionality does doing

How to find an object in a Set of custom objects

The code below contains a Set of CustomObjects. I am trying to search an object in it. I’ve overridden equals() method to match it with a specific field, am not able to understand why is it not able to find it. “XXtNot FoundtXX” is getting printed instead of “Found!!” import java.util.HashSet; import java.util.Set; Answer You haven’t overridden equals and hashCode