A Set is a collection of elements in which each element can only occur once. A Set does not have a specific order and does not provide a way to access its elements by their position.
To check if a string is equal to null in Java, you can use the == operator.
When overriding the equals() and hashCode() methods in Java, you should consider the following issues:
The equals() and hashCode() methods are two methods that are defined in the Object class, which is the superclass of all classes in Java.