Hashtable does not allow null keys or values, while HashMap allows null values and 1 null key. Questions: Why is this so? How is it useful to have such a key and values in HashMap?

Why is it useful to have null values or null keys in hash maps?

Created Sep 1, 2010 Edited Sep 1, 2010

Viewed 56970

Hashtable does not allow null keys or values, while HashMap allows null values and 1 null key.

hashmap java