Map and HashMap in Java - Full Tutorial

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Maps and HashMaps in Java can be so confusing when you're first starting out your Java career.
But Maps and HashMaps don't have to be confusing at all! A Map is a simple, powerful tool to have in your programming arsenal, and this video will give you everything you need to know to use Map and HashMap confidently in Java, even if you're a Java beginner.
Learn or improve your Java by watching it being coded live!
Hi, I'm John! I'm a Lead Java Software Engineer and I've been in the programming industry for more than a decade. I love sharing what I've learned over the years in a way that's understandable for all levels of Java learners.
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[@gur151]

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[@CodingWithJohn]

Thanks! As you for sure already know, liking/subscribing/sharing/commenting all really help, so I really do appreciate it!

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I feel the same way as you Gur.

[@iskandar-9726]

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[@blazing_yt2342]

Amazing explanation man, you actually made mapping easier.

[@yuto5636]

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straightforward, structured and contains the essentials. Thanks for this good video!

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[@Devivl]

One of the best. Short and clear. Thank you, John!

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[@CodingWithJohn]

Thanks Pedro! I appreciate all the comments, keep up the learning!

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[@BernardVisagie]

2:28, now in C# you can infer even more, and you would be able to write your Java as: HashMap empIds = new();

[@Rowa_n]

this is very helpful! thank you so much for making this tutorial! it was easy to follow

[@xiangyuliu9629]

pretty clear, cut to the chase, love this video, subscribed already.

[@sigfigronath]

This is so simple wow, thanks John!

[@szaryn]

Yo! Clear, straight-forward, and fun explanation. Thank you so much, John! ^^

[@flytoinfinityvivi]

This video literally equals to an hour of studying trying to understand Map. You are amazing! Please never stop what you are doing. You actually make us beginners understand and well hopefully making us the future IT people (:

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This was very helpful and easy to understand. I really appreciate it, thanks.

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This is truly some of the best coding instruction I've found online

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Very good videos, I am already watching many of them, you explain very well, I hope your motivation continues! +1 follower

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Fantastic video and such a well put explanation, easy and fun to follow along. Thanks a lot!

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I tell you now. You will become top code KZbinr

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Thanks for the words of encouragement and thanks for watching!

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Spent hours reading book but explained it so simply. Thank you.

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I love the way you explain Java Subjects, you make me feel like it is not really that hard.

[@To4ster0ven]

hello john. im a day before finals in one of the courses in java that i learn and this video has explaind the hashmap so well. thank you so much

[@jyotvkathalu7901]

It’s a very crisp and detailed explanation… i was waiting for you to explain iterating maps … thq for video

[@karthikm5507]

Crisp and clear. Really liked the way you explained.

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Thank you for uploading such great content and educating us. Your explanation is so precise and concise.

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I just subscribed to the channel just watching one video, so specific, clear concise..keep rocking..

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Tnx a lot for ur videos, i really enjoy how u represent the agenda and especially ur english

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Thank you John for such crisp and clear explanation.

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Awesome! This is Clear and easy to understand

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Best video I've watched on any Java data structure! Thank you sir!

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Concept is crystal clear now. Thank you!!

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This is exactly the video I was looking for! Thank you!

[@Diana_13.]

A huge thanks to you.The way you talk is so clearly also for none English speakers...🤝👏👏👏

[@pandadoskoi]

Thank you so much. I certainly had my struggles to understand what Maps in Java are and what their purpose is, my scripts from university read like messages from outer space... but now I at least have a clue to get further in learning. I felt so stuck with this topic and felt so stupid because everyone said "oh, maps and hashmaps are so easy". Again, thank you effin much. Left a like and sub! :)

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Clear, no BS, concise. Just subbed

[@HatTrick4030]

Amazing!! understood HashMaps within 5 minutes 😎. Super Thanks

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I've been lucky enough to go from about 10k a month ago to over 50k now and growing. So it's taken a long time but I'm on my way. Thanks for the kind words, glad you're enjoying the videos!

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[@evgenystep8897]

Super easy explanation thx to clear out how to easily use HashMaps!

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I like the way of simplicity in explaining the HashMap topic. 👍

[@jakedotnet]

9:09: The error 'Insert "Dimensions" to complete ReferenceType' refers to arrays. The primitive type int isn't a valid type to use here, but int[] would be a valid type, as all array types are reference types in java, even those of primitive component type.

[@MarkSmith-vo1vn]

Oh because int [] array is an object as well. We just need to pass in an object, so it thinks we want to do the int[]. Makes sense thanks.

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Great tutorial, helped me alot with my Java assignment :)

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thanks John for this well-explained tutuorial

[@btmahvash]

Excellent, I learned very well