Hashmap in java?

Question

What is the difference between hashmap and hashtable?
Can we use INTEGERS as Keys for accessing?

Answer 1

Nishtha

HashMap

-They are non-synchronised.
-They aren't thread safe.
-That means multiple threads can operate -same on map object at a same time.
-Because it's not a thread safe so the -performance will be high.
-Null insertion allowed for both key and value.

Hashtable

-They are synchronised.
-They are thread safe.
-That means only threads can operate a object at a time.
-Because it's a thread safe so the performance will be low.
-Null insertion not allowed for key and value.

Yes you can use Integer as a key.

For Internal working of Hashmap:-

https://www.sololearn.com/post/501453/?ref=app