LinkedHashSet on objects without overridden hashCode() and equals()

Question

I have the following collection of objects:

Set<MyClass> test = new LinkedHashSet<MyClass>();

but MyClass does not override the hashcode and equals methods.

Can have the above collection only unique objects even the MyClass does not override the hashCode and equals methods?

Answer 1

The default implementation of equals is to check identity (i.e., use the == operator). Your LinkedHashSet (or any other HashSet, for that case) will contain unique objects in the sense you won't be able to add the same object twice. However, if you create two instance exactly the same way (e.g., pass the same arguments to the constructor), your set will still contain both of them, as they are not equals.