In Java HashMap each bucket is assigned a unique identifier and that identifier is the hashcode of the key.
What i means is if the key's hashcode is say 236 then HashMap bucket will find bucket whose identifier is 236 and put key-value pair
Could anyone please let me know if my above understanding is correct?
If above correct then -
All key value pair with same hashcode will be present in same bucket they might not be equal using equal() method.
It depends how many buckets there are. The Map implementation uses an array of buckets, and uses the hash code to find the bucket. Apart from that, I think you are correct.
There was a discussion about that recently: try here. That will probably answer some of your question, so if there is anything you still need to know, please ask again.