How to use HashMaps in Java || Hashmap in java with example program - Part 5

Java HashMap class implements the map interface by using a hashtable. It inherits AbstractMap class and implements Map interface.

The important points about Java HashMap class are:

A HashMap contains values based on the key.
It contains only unique elements.
It may have one null key and multiple null values.
It maintains no order.
hashmap is non-synchronised -- not thread safe
It gives Concurrent modification exception -- in case of Fail - Fast condition

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[ayushsaxena]

Such a great and precise explanation for HashMap. Those 27 minutes are totally worth watching.

[Duru_gaming_experience]

Your way of explaining is awesome.Just one time watch the video n you will get the concept

[saikumar-ehdf]

HashMap does not allow duplicate keys but it allows to have duplicate values.

[smrutitech]

Hey Naveen 1 of my friend suggested your channel. And from that day onwards i am waiting your videos and i m loving it. So i want 1 program from you that question asked by one person in an interview. The question is : 1 person did 3 person's work in 2 days to get 4 prizes and 5000 rupees as bonus.
So the o/p should be we we replace the 1 person as one person 3 person's would be three person like this. We should replace the numeric to alphabets. Request you to can you please do it with what ever logic and the concept are coming in to your mind. I want all the possible way you can.

[Jyotigupta-vsmz]

In love with the way you explain and the voice 😍♥

[pradeepteja-teem]

Thank you So much Bro for Wonderfull Explanation.

[sonalpatel]

Awesome explanation!!. Please share all your tutorial for java and Selenium.

[neerajsri]

Hi Naveen, what software you have use to record this video?

[rkaravind]

Hi Naveen, Thanks for sharing Collections information. But Set interface is missing. Please kindly share that so it will be a complete playlist.

[hilalaiss]

I have a question,
what about if we define the hashMap to receive a string key and string value but for some reason we need to store an abject as a value after converting it to a string (obj.toString())
in this example if i traverse the hashMap and i need to access to one if its fields, i could not because it is converted to a string, What i s the solution for it ? thank you

[dikshasmriti]

Your tutorials are awesome sir. Big fan of yours. 😊

[RajeshKannanMarkandan]

Hi Naveen, Please update your latest code and codes which are not there in your Git repository.

Thank you.

[aischacelik]

Now I understand the construction of HashMap. But how I can change parameters, values with the "Entry" and "Set"?

[alammohammed]

thanks, and also if you have time please give me this ans:- i want to where We implement in real time project polymorphism and Abstract class and method

[sumantpatro]

Hi sir, when i m trying to insert values hm.put(1, "selenium"); an error throws saying java: <identifier> excepted. Can u please tell me what to do?

[safarnama]

Hi Naveen, how can we write nested hashmap(string, list<hashmap(string, string)>) into Excel

[ferfykins]

I'm confused about something with hashmap, you said it does not maintain order, but when you printed out the entire employee entryset, it did it in order by key, 1, and thanks for the videos, love your channel! :)

[shaunakpoddar]

Hi Naveen,
Can u plz give example of concurrent hashmap?

[diptendumukherjee]

while iterating the map, what is the Entry class used for?

[desertstar]

How to use HashMap in our Selenium code ? I was asked in one of my many interviews. It is important as to why we are learning HashMap and what is the use of it..