Java Enums Explained in 6 Minutes
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- Опубликовано: 27 сен 2024
- All about Enums in Java - Full tutorial with concrete examples.
Enums (short for Enumerations) are used in Java to hold types that have a certain finite set of values. But if you're new to enums, they can be a little confusing. In this Java beginners' tutorial video, we'll talk all about enums - how you can create your own enums, how to use them, and in what situation using an enum makes sense in your code. All in less than 6 minutes!
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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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How does this man manage to break down these concepts so effectively, especially at such a quick pace?! These videos are a godsend. The way you add a small piece of code then fully explain why you added it and what it does makes the code extremely easy to understand. The humour along with the simple but creative programs is also a huge plus, very engaging. Thank you!!
The mutability of Enum fields is a nugget of wisdom, which i didn't anticipated. Thanks!
Hi. I've only recently become aware of your RUclips channel, and I wonder why the RUclips algorithm hasn't recommended your channel earlier.
I like your succinct videos a lot, and they are superbly suited for my computer science school courses, since Java is the language students learn in higher education in Germany.
Thanks a lot for the high-quality content.
you can help by like and subscribe, that boost the youtube algorithm
it could be because you are subscribed to many channels, try using two account (it can provide SOME of what you need )
I am so glad that whenever I don't understand something in java, your videos are top on the list!!
Man your videos are so clear even to me, who can't speak english at all
I am trying to improve my proficiency in Java. I found your video very insightful and it allowed me to practice and adapt new coding immediately. I found the enum concept quite difficult to adapt into real usage, whilst looking at numerous other sources. Its application in code is making much better sense now with a strong example.
sir
thanks so much
I really appreciate
I taught myself frontend development two years ago and I got hired recently as backend engineer.
since I recently started learning java , I was struggling on something on my assignment and this video basically explain everything.
your example is similar to the problem I have .
I right away subscribe and will recommend this channel to my friend
I want to say thank again
You’re making my life much easier thank you so much man i really appreciate you
Amazing! now I don't have to watch a 30 minutes of enum video tutorial again on a purchased bootcamp on Udemy. just simple and and understandable. all that matters to us is to understand the syntax of a new lesson and master it and then we can build our projects with details ourselves. the problem with other instructors is that they involve too many peripherals to the main lesson and we understand all except the main topic :D
These tutorials are amazingly clear and understandable. I'm so grateful because that's not always the case with coding tutorials.
Please make Java development full course, they way you explain it's really easy to get understand concept. Thank you
We had to implement the 2nd part of your video(with grades instead of cereal) as part of my exam(on paper). Without you, I would not have gotten it correct. Thank you!!!
Hey, you may not remember me, but I watched one of your I/O java videos a couple of weeks back and I just wanted to say thanks for the clear straight forward but most importantly amazing Java tutorials you've put out
Bless you and your video(s). I started studying for the OCA and your videos are a big help in understanding the dry text from the book in minutes (literally), haha.
This man makes a boring lesson to a lesson to be a fun and more enjoyable lesson.
Hi sir, I've finished the core of java and I am now practicing it daily, and I started to explore more on advanced level and I'm going to start it in java enums. Thank u sir for sharing this. I'm really looking forward for your future videos about java. New Subscriber here!
Where do you go to practice java?
What do you mean practicing it daily? How are you doing that?
Hi John, another nice thing about enums is that you can use abstract methods to customize the constants :)
One thing about John is he picks the right examples that makes one watch and never forget the topic….In this case cereals 😂. Good job man 👍
You broke it down really well!!
Clear and crisp. Thanks for video. Subscribed.
Thanks as always John!
My knowledge++
Straight to the point, and very pedagogical. I have already subscribed, but I like is coming right up.
I understood it is more like a class which contains its own instance fields as static. for example class test{ static test monday = new test(); static test tuesday = new test();} Thank you very much!!!!!!!
What a heck of explanation man, moreover super creative using cereal, thank you
Thank you for sharing! Love the names you give to them and also the shortcut tips!
Nice on John, short clear and detailed.
How come this has so few views and likes. Excellent video mate, keep it up please!
Loved that! Any tutorial for Strams please ?
Ohh, I really like your sense of humor and how you explain things, even though it was a bit fast. But maybe I'm just tired^^
Anyways, thank you for this great video!
Your videos help me a lot. Thank you so much!
final is what makes something constant, and also immutable. If all the fields of a class are made final, then the state of that class is unmodifiable. Which makes the type immutable. At least this is my understanding of it. A handy tip, the data members held by a class/object are what constitute it's "state" and methods make up it's "behavior".
This channel is pure trasure
Something missing here is the importance or ordinality. As in most other languages implementing enums or ordinals the items in the enumeration have an ordinal value...the order in which the enumeration's items are defined IS SIGNIFICANT. This can create problems in a project if developers try to re-order the items later on...something which should not be done. This idea of ordinality also has repercussions when mapping to a database. Most databases map enums to a column using the ordinal value by default. Just don't forget the ordinality.
Helpful as always
I watch all your videos even though I know about the video .. keep it up john!
Ha, well thank you!
Me too. I love seeing how he describes it in such a short time without saying anything flat-out wrong which would be so easy to do when trying to make really short videos.
wow! A gold nuget of information. thanks a lot.
Amazing break down John, thank you!... Now if only we can get you to reassess these gradings for deliciousness. Captain Crunch is 110/100 LOL!
Tysm for this video! I had watched another video on enums, but somehow errors were being thrown in my program and I didn't understand the purpose of enums, nor how to use them and now I think I have a clear basic understanding of them. Plus, I really want some cereals now lol
1:17 IntelliJ tells me that the semicolon is unnecessary, and the enum compiles with or without it; was it required in an earlier version of Java?
Great explanation 👏👏..Thank you for the refresher👍👍🙏
Great explanation, thanks!
W video, probably saves me from a negative grade :)
This was helpful 👍, thanks !!
4:32 - You thought we would not notice, but we did :)
Real question, what design pattern do you use when you have enums that are constant values that need to contain a field that is an object whose internal values need to be changed across instances? For example, if you have different kinds of web input fields in an enum, and you know for certain the type of data type each field returns (String, int, boolean, array, etc) so you want to assign a corresponding validation strategy to each, however, in the strategy maybe you want to validate different values against the result across different input fields of the same type. This is my particular problem however i hope this represents the underlying design question i have!
can you do a video about dependency injection?
Good toturial Mr.john
Another simple and amazing explanation as always. ❤💯
Can not thank you enough!🙏
Hey John, thank you for sharing your experience. I have watched couple of videos and became the fan of your explanation.
If you don't mind, may I know which theme you are using in your Eclipse IDE?
it's looking cool.
It's a plugin called Darkest Dark
@@CodingWithJohn Hello John. Could you make a video covering these things in eclipse like Maven, gradle, ant build, mylyn etc. ? Would be quite informative for beginners. Eclipse tends to overwhelm you with all these terms sometimes.
Thank you, great video.
Thank you, your explanations are very clear ❤
Thank you very much, John! 🙂
Great content John thanks
Surprised you didn't include the abstract methods in the ENUM's as another way to give them more features, ie:
public enum Test {
MY_VALUE_NAME {
public String myReadableValue() {
return "My Value Name!";
}
};
public abstract String myReadableValue();
}
usage:
Test.MY_VALUE_NAME.myReadableValue();
Output:
"My Value Name!"
Nice and quick tutorial. Thanks
Holy broken sewer pipe batman, thank you. I've been trying to figure out how to use enums for the past few hours. THANK YOU!!!
You are born a teacher! did you know that?
This is simple and precise...may be some additional details like getting the ENUM by passing a value like deliciousness would be great
Hi John, Could you please add an example video to see how to use switch case with enums
All this programming stuffs make me have a headache, but anyway it's fun!
many thanks dude !!
Nice and concise, awesome video!
Thanks man, this actually helped me a lot :D
I learned something!
50/50 mix of Reese's Puffs and Cocoa Puffs for the win!
This is an interesting proposal. But doesn't that just dilute the peanut-butteriness of the cereal by adding additional chocolate to the already existing perfect mix of peanut butter and chocolate that is the Reese's Puff's recipe?
@@CodingWithJohn Excellent point. 😃
thank you
Can you do a video on Stacks and Queues please
What can I say, you are the best!
Awesome Video!
OK, I'm just gonna confess my sin: I dev'd with Java for a very long time and I still sometimes use enums for stuff I should better be using a database. They are just so handy. Screw the inefficiency large enums create because of overhead, I wanna make life easy for me and I like switch statements lol
haha
Could you add Java certification series as well.
you could also set the level of delicousness to private
So an enum is like a conglomeration of maps or dictionaries for a specific list of things?
If you declare a Constant Enum the semicolon is optional
lovely video dude
Awesome Thanks!!!!
love you john.
Thanks, very very clear
dear john good job .please speak slower . many people who interested in your videos they are not english speakers but whatever you are very good in teaching and thank you very much.
John ,can you tell me what is the type of "enum values" like ,if MONDAY is not a String than what it is??
and can we me numeric enums?
Great content
What if we use the lowercase values for enum class
excellent!
Thanks
Since this video was made on a Monday I think it was a while away from Friday lol.
Very controversial video.
is this a refreshment after collider and subs?
I am going through Enums that were introduced in Java 1.5. In Effective Java 2'nd Edition it's mentioned that before Java 1.5 there were int and String enum patterns which were having some deficiencies.
I understood the cons of int enum patterns but while going through String enum patterns I got the basic idea but didn't get the deep sense of below statements mentioned under Item30 in Effective Java:
This variant, known as the String enum pattern, is even less desirable. While it does provide printable strings for its constants, it can lead to performance problems because it relies on string comparisons. Worse, it can lead naive users to hard-code string constants into client code instead of using field names. If such a hard-coded string constant contains a typographical error, it will escape detection at compile time and result in bugs at runtime.
Can anyone help me in understanding what these lines explaining. I would appreciate if it can be explained with some code snippet.
Thanks
Can you explain to me how Enum is used? I don't know why I would ever use an Enum.
is it simply a list of a final expressions?
Just nitpicking: I would argue for using singular in the enum name. So DayOfTheWeek instead DaysOfTheWeek.
Why would I prefer an enum (I didn't know that this is how you should pronounce it!), over a static variable and methods?
im not sure if i got it right but is every day of the week inside that enum like a constructor in it self, coz u are treating them like they are, just wanted to be sure that im getting it, if u can explain this
Why the semi colon?
it was great. thanks
Great promotion...1:36
How to implement this is ruby?
fantastic!!!!
I tried that but my "Finish" is deactivated. any help?
I never get to use enums in my programs, because I end up needing to convert them to classes or interfaces.
I’m waiting for the day someone asks me to code the solar system or something. I have my enums ready
* Come to think of it… I wonder if any of my static members can be replaced with enums (if they’re in groups)…
wonder whether i can fill an array with enum elements?