1) The underlyingdata structure is Hashtable.
2) Duplicate keys are not allowed but values can be duplicated.
3) Insertion order is not preserved and it is based on hash code of the keys.
4) Heterogeneous objects are allowed for both key and value.
5) Null is allowed for keys(only once) and for values(any number).

Leave a Reply

Your email address will not be published. Required fields are marked *