here to get updates on new
1. Set is the child interface
2. If we want to represent a group of individual objects
as a single entity, where duplicates are not allowed and
insertion order is not preserved then we should go for Set.
3. Set interface doesn’t contain any new methods.
So we have to use only Collection interface methods.
1. The underlying data structure
2. Duplicates are not allowed. If we are trying to insert
duplicates, we won’t get any compiletime or runtime
errors. add() method simply returns false.
3. Insertion order is not preserved and all objects will
be inserted based n hash-code of objects.
4. Heterogeneous objects are allowed.
5. ‘null’ insertion is possible.
6. implements Serializable and Clonable interfaces but not
7. HashSet is th best choice, if our frequent operation
is Search operation.