Bucket number for null key in hashmap

Question

In a hashmap what would be the bucket number of null key? I am Trying to learn internals of hashmap if any one can give me good video tutorials it would be appreciated.

Looks like trying to solve issue sitting on interview – Andremoniy Nov 09 '15 at 09:07 — Andremoniy, Nov 09 '15 at 09:07

score 1 · Answer 1 · answered Nov 09 '15 at 09:20

1

HashMap, handles null key differently. For the null key, default value of hashcode is 0 and the first bin/bucket will be used to place it as per the HashMap implementation

From HashMap class

 static final int hash(Object key) {
        int h;
        return (key == null) ? 0 : (h = key.hashCode()) ^ (h >>> 16);
    }

Internally HashMap maintains array of Entry class(internal class of HashMap which is used to store data) which is also called as Bucket. Entry class contains key, value, nextElement, hash-value variables.

Data with null key is stored at Bucket location 0(array index 0 of Entry array). Hash value is also zero for null key.

Source

answered Nov 09 '15 at 09:20

Ankur Singhal

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*If you don't aware of bucket,then keep away man....* - is the response you get when you try to tell the OP the same thing. LMAO – TheLostMind Nov 09 '15 at 09:39
@VinodMadyalkar Yes i have gone thru comments, i have flagged it – Ankur Singhal Nov 09 '15 at 09:40
He is like lkg student.Don't know how to talk.sitting here to demotivate others. – Anandhu Nov 09 '15 at 10:53

Bucket number for null key in hashmap

1 Answers1