HashMap Interview Questions | Interview Preparation

[@rahulkhandelwal46578]

Frankly speaking, I just searched Hashmap interview questions, though I was going with the first search result then suddenly I saw byte programming and I went here. Very informative videos on your channel.

[@manojmajumdar3815]

This channel definitely deserves more subscribers . All the questions asked in this Hashmap video are explained in-depth.

[@ByteProgrammingVedantHarish]

Much appreciated!

[@pallavidesai1133]

Please make more videos for java..you are the best trainer. Thank you so much

[@Hacks00145]

Thanks for video.

[@basavarajnv1017]

Thanks so much Sir.. Really nice video ,very informative 🙏

[@yoshitamahajan353]

Hi what exactly do we have to write inside hashcode() method when creating our own custom class? As we need to override hashcode method so what content should be present inside hashcode if we have to write the content inside hashcode() method?

[@ByteProgrammingVedantHarish]

@Yoshita : Hashcode is used to calculate index. Try using permutation of hashcode all fields and multiply with 2 or 3 prime numbers.

[@yoshitamahajan353]

@@ByteProgrammingVedantHarish thanks

[@yoshitamahajan353]

Which underlying data structure does hashmap follows? Arrays or some other?

[@ByteProgrammingVedantHarish]

@Yoshita Hashmap internally has array and each node can contain linkedlist or tree.

[@yoshitamahajan353]

@@ByteProgrammingVedantHarish thanks

[@amscoder5262]

The underlying data structure in case of HashMap is "Hashtable"

[@theupdatetracker8598]

Very nice sir..Very informative.. Please explain utilzing the custom key part, where we need to override equals hashcode methods in detail(example) if possible ..and please make one vid on concurrency and concurrent collections.. Thanks alot 🙂

[@ByteProgrammingVedantHarish]

Sure! Stay tuned!

[@indexOutOfBound]

If we do these in the hashmap--- hm.put("1","Ram"); hm.put("1",Shyam); Then 1 will hold Ram/Shyam ? and what will be hm.get("1")?

[@ByteProgrammingVedantHarish]

@Vishal Keys are unique in java. hm.put("1", "Ram") => hashmap output :{1 = Ram} hm.get("1") => Ram hm.get(1) => null //key is int, no value present for this key String putVal = hm.put("1", "Shyam") => hashmap output : {1=Shyam} hm.get("1") => Shyam hm.get(1) => null //key is int, no value present for this key putVal value => Ram Hope it helps.

[@1msubscribers214]

It will return shyam ... Value will override...