Today, I crashed production because I didn't review and test my code. This was a valuable lesson for me. A colleague with more experience showed me how I could have detected this error through unit testing. We wrote 8 test cases within 20 minutes that could have assessed the functionality of my changes, and I would have noticed the bug. I am glad that we have an open culture for acknowledging errors, and that I was 'allowed' to make this mistake.
I didn't realize how I had caused this error until we received emails from the company. In a mapper method, I used .filter(Objects::isNull) in a stream filter instead of .filter(Objects::nonNull). This led to the occurrence of the error on 6000 devices. It dawned on me that a slight oversight can impact hundreds to thousands of people. From now on, I will be more conscientious and refrain from putting my code into production until I am 100% sure that it performs its intended function.
These are all wonderful. I'm a retired Java 6 programmer writing Minecraft mods in Java 8, 16, and 17. Your videos are clear and concise! They help me a lot.
Very noice!!! As a “beginner” learning on my own these lectures are important lessons. Great Intro exposure to thinking about writing code holistically. Ty. 🙌🏿🙏🏾
Hey John! I took a course in the fundamentals of computer science last year where our professor mentioned the importance of unit testing and made us all write our own ones without really explaining the reason why or showing how to properly do it. This video really cleared that up for me. Thank you so much!
A video on lambdas expressions would be so awesome, especially when the concept is partnered with runnable class instances. These together are the only way I know in java to make a responsive GUI application.
I need to give John some major KUDOS. I actually followed the link to his course and now, after like 10% in, I've learned at least 4 or 5 new things that are going to make my life so much easier. Thanks buddy for making these videos and adding a course. Ternary alone is going to save me so much time. A+++
Awesome, thanks! I just added the ternary lesson earlier this week, glad it's helping! I'll be continuing to add new lessons as I'm able, and anyone who has the course already will of course have access to new lessons that are added as well, forever. Also with your permission, if you're ok with it, I might also use your very kind words as a testimonial!
Run our test with coverage, John all the expected points you explained in a very simple way , Thanks for your hard work nd keep on doing such a great real time videos
Had an assignmen to perform unit testing in Java usign the Junit . Was recommended to watch this video of yours . Your doing a great job ceating content for beginners like me Sir John . Had to subscribe ! Keep up the good and humble work !😇
I'm really thankful to you. I'm currently in the process of studying. And I researched it because my doctor didn't talk about it and I found a similarity between it and the Java language, but it's not a regular Java, it's a test for Java. Thank you. I really understand. And of course I'm proud of myself because I researched who you might laugh at. But that's true. Thank you again❤
Hi John, thanks for the video. I have to write my own unit tests for a project assignment, but have never done or got properly shown how to. This video cleared all my questions.
Thank you for this video. It's clear that this video is just a summary of what unit tests are just like you said. However, only your video was able to really make me understand what unit testing in Java is about.
Learning Hamcrest is in my opinion another essential library to have a good understanding of. Hamcrest library makes asserting test cases more flexible & intuitive
I enjoyed the topic of the video, since unit tests are not necessarily what you have to do at school (and it's not in the curriculum). What I also liked was you switching to IntelliJ. I've been experimenting with my students, and we tested 3 different IDEs. They said that they felt most comfortable with IntelliJ and also appreciated the helpful tips that guided them towards fixing errors. I'd also like to give you props for the way you present the topics, among them being voice, intonation, gestures and pace.
Truth to be told, curriculum for computer science in most university is outdated. Most lecturers stopped learning new things whereas the cs world is evolving every second.
We actually have a course that goes all in on these features. It feels a bit awkward to do this much stuff for a conceptually small assignemt project but still something practically useful.
whenever you have covered a topic, you have become my go-to guy to learn new things. It would be awesome if you covered mocking frameworks as well like Mockito which are probably unavoidable for a developer.
@@shukria485 Yes, I am self taught. Java is not that difficult language to learn if you spend the time to learn it, if you have any questions about Java, let me know, I will help you if I can. Good luck.
You are great John ! I really enjoy your videos, they are so practical but with a lot of useful information and knowledge. You do that complex topic looks really easy and funny. Keep with this awesome work. Thank you !
Exactly what I need at my level. I'm at the point where I can make my own software, but my code is all spaghetti and it takes a while to debug. Now I'm going to get into the habit of testing it early and often.
Just want to say these videos are great and such amazing quality. I would definitely pay for a data structures and algorithm course after completing the Java course.
Hi John, you have not written test for the input number greater than 100 which should return invalid value but in the above code it would return an 'A'
Thanks for your video. I almost see all your videos. So Could you make more videos like the tools, Maven, or Git, or deploy projects into AWS. Thank you so much.
Great 👍🏽 introduction. Can you do advanced unit testing that involves configuration of the test class itself and adding mock beans etc before writing the actual unit tests? Thanks 🙏🏽
I'm loving your channel! I'm a teacher, and we do a lot of writing in the main method (at least at the beginning of the year. How would I test a certain output of the main method. And how can I test to make sure they used a print vs printf vs println in their code?
Hi John.love your videos..you explain both concepts and code very clearly..could you please do a video around stack/queues and bfs/dfs algos? Thanks a lot :)
Your channel is pure GOLD! I'm learning more in a few minutes than an whole semester of classes.
So true
Today, I crashed production because I didn't review and test my code. This was a valuable lesson for me. A colleague with more experience showed me how I could have detected this error through unit testing. We wrote 8 test cases within 20 minutes that could have assessed the functionality of my changes, and I would have noticed the bug. I am glad that we have an open culture for acknowledging errors, and that I was 'allowed' to make this mistake.
I didn't realize how I had caused this error until we received emails from the company. In a mapper method, I used .filter(Objects::isNull) in a stream filter instead of .filter(Objects::nonNull). This led to the occurrence of the error on 6000 devices. It dawned on me that a slight oversight can impact hundreds to thousands of people. From now on, I will be more conscientious and refrain from putting my code into production until I am 100% sure that it performs its intended function.
How are ya'll getting jobs out here not knowing how to test your code ;-;
These are all wonderful. I'm a retired Java 6 programmer writing
Minecraft mods in Java 8, 16, and 17. Your videos are clear and concise! They help me a lot.
Very noice!!! As a “beginner” learning on my own these lectures are important lessons. Great Intro exposure to thinking about writing code holistically. Ty. 🙌🏿🙏🏾
we should be friends lol i'm also just started Java! maybe CodingMates?
@@mohamedibrahim-qm1cr where are you in your journey? Are you taking a course? With who? Asking for potential friend. Lol
@@mastershonobi110 just in java for a week now, I'm in a bootcamp plus resource from Plural Sight.
Yes, John's instructions are clear and to the point.
@@mohamedibrahim-qm1cr Which level are you in? Did you reach objects and inheritance?
Hey John! I took a course in the fundamentals of computer science last year where our professor mentioned the importance of unit testing and made us all write our own ones without really explaining the reason why or showing how to properly do it. This video really cleared that up for me. Thank you so much!
A video on lambdas expressions would be so awesome, especially when the concept is partnered with runnable class instances. These together are the only way I know in java to make a responsive GUI application.
i wish this dude made spring boot videoes would be gold
You're brilliant! I'm a senior Java developer but I don't have these didactics and ease to explain/teach. Awesome job
I need to give John some major KUDOS. I actually followed the link to his course and now, after like 10% in, I've learned at least 4 or 5 new things that are going to make my life so much easier. Thanks buddy for making these videos and adding a course. Ternary alone is going to save me so much time. A+++
Awesome, thanks! I just added the ternary lesson earlier this week, glad it's helping! I'll be continuing to add new lessons as I'm able, and anyone who has the course already will of course have access to new lessons that are added as well, forever.
Also with your permission, if you're ok with it, I might also use your very kind words as a testimonial!
@@CodingWithJohn Absolutely. 100%
Sent you an email.
Hit the like, if you have been watching many tutorials and finally, you get the proper context with clear explanations.
"run our test with coverage" was a requirement for project...Its clearer now. That was a treat. Great video
Run our test with coverage, John all the expected points you explained in a very simple way , Thanks for your hard work nd keep on doing such a great real time videos
Had an assignmen to perform unit testing in Java usign the Junit . Was recommended to watch this video of yours . Your doing a great job ceating content for beginners like me Sir John . Had to subscribe ! Keep up the good and humble work !😇
Awesome, I'm glad it helped! And thankful to whomever recommended it!
going through your classes while taking part in a bootcamp. really appreciate your help!
Glad it's helping!
I'm really thankful to you. I'm currently in the process of studying. And I researched it because my doctor didn't talk about it and I found a similarity between it and the Java language, but it's not a regular Java, it's a test for Java. Thank you. I really understand. And of course I'm proud of myself because I researched who you might laugh at. But that's true. Thank you again❤
Hi John, thanks for the video. I have to write my own unit tests for a project assignment, but have never done or got properly shown how to. This video cleared all my questions.
This is the best beginner friendly unit testing tutorial I've found so far
Every time i look up something on youtube regarding java, and I see johns video available on that topic, what a sigh of relief, hushhhh.! 😅
Let me know if there's something crucial I haven't covered yet!
This video makes the JUnit test case more easily to implement. Thanks. 🎉
now 2:23 am, but I'm sitting and watching you.
It's so cool. Firstly I'm learning Java, secondly I'm improving my English (at least listening)😍
The one testing framework I've ever loved and enjoyed was RSpec for Ruby or Rails. Extremely easy to setup, read and write tests.
Thank you for this video. It's clear that this video is just a summary of what unit tests are just like you said. However, only your video was able to really make me understand what unit testing in Java is about.
This video really helpful for my next task.Thank you so much John.
Best video ever on JUnit by a long shot. Would really love to see more advanced videos on this topic!
I've always been scared of Testing, thanks to this video, I feel quite comfortable with it now.
i have not understands this topic in my class but now i am perfect with this topic.... Thank you professor
Been exposed to introduction of JUnit today, lucky to have this lesson!
Learning Hamcrest is in my opinion another essential library to have a good understanding of. Hamcrest library makes asserting test cases more flexible & intuitive
I enjoyed the topic of the video, since unit tests are not necessarily what you have to do at school (and it's not in the curriculum).
What I also liked was you switching to IntelliJ. I've been experimenting with my students, and we tested 3 different IDEs. They said that they felt most comfortable with IntelliJ and also appreciated the helpful tips that guided them towards fixing errors.
I'd also like to give you props for the way you present the topics, among them being voice, intonation, gestures and pace.
Truth to be told, curriculum for computer science in most university is outdated. Most lecturers stopped learning new things whereas the cs world is evolving every second.
im taking a junit class rn and its a complete joke of a class.
We actually have a course that goes all in on these features. It feels a bit awkward to do this much stuff for a conceptually small assignemt project but still something practically useful.
so true. intellij is the better of them all, and its free
@@albertbokor6643 must be nice
Amazing how much you covered in 21 minutes!
I have been watching since a year. Your videos are very simple to understand. Thank you.
whenever you have covered a topic, you have become my go-to guy to learn new things. It would be awesome if you covered mocking frameworks as well like Mockito which are probably unavoidable for a developer.
Hey John, kindly make one session for Intellij ide usage for java and maven plugin nd other which will make code coverage
Your videos are GOD SENT! As a person that just started their career as a Java Engineer, I thank you. Keep up the good work.
Keep at it, Java is really nice language.
Did you learn byyourself? I'm on that journey
@@shukria485 Yes, I am self taught. Java is not that difficult language to learn if you spend the time to learn it, if you have any questions about Java, let me know, I will help you if I can. Good luck.
@@theblindprogrammer that's awesome thank you so much.
I'll pass a string for ut algos to pick up John. He deserves million subs.
Simple and precise illustration. Thank you John. Probably including parametrized junits supported in Junit5 would be better.
Thanks a lot John. I started loving Java after watching your videos! This topic was so interesting.
Can you do a video about Heap sort and also Time complexities?? Thank you!!!
You are great John ! I really enjoy your videos, they are so practical but with a lot of useful information and knowledge. You do that complex topic looks really easy and funny. Keep with this awesome work. Thank you !
Exactly what I need at my level. I'm at the point where I can make my own software, but my code is all spaghetti and it takes a while to debug. Now I'm going to get into the habit of testing it early and often.
This video has made me subscribe. So well spoken and well communicated I had no choice! Thank you for this very informative video
Thanks a lot!. I wish you could create a video on Unit Testing for Spring Boot Application as well in near future
needed a refresher as i apply to sdet jobs. excellent clear stuff. thanks.
About time you started using intellij
Thanks John, I understood the basics of JUnit test in Java through your easy to understand examples. 😊
thanks this clarified a lot that the textbook wouldn't cover
Appreciate you and this channel ... would love to see you cover mockito!
U are amazing bro. For one video, I understand Unit testing.
Just want to say these videos are great and such amazing quality. I would definitely pay for a data structures and algorithm course after completing the Java course.
Hey little John, you’re like a Robin Hood of teaching!
I attended a 3 hour class which taught me about 75% of what you covered. Your video took 15 minutes...
same
This guy knows everything about java 🤯
Master of coding 🙌 👏
Hey John, congrats for your content. It's really clarefull and understood. Thanks from Brazil, let's keep coding.
Nice work! Really informative video and easy to follow along on
Wow I pretty much appreciate you John I am so happy to get your channel
Awesome overview and introduction to JUnit, thanks!
I wish you had a full spring boot tutorial course
Your contents are really helping
Awesome vid John, thanks for going into so much detail in an actual use case!
Great intro to unit testing John, awesome! Thanks!
Really good teaching. Thanks for sharing this video.
I was so great ful for born in this era.
Good starter video for unit testing
John you are the best of the best. Keep it up and would like to see some Spring boot tutorials. Many Thanks
Please make a video on Design Patterns John!!
very good explanation , I will use more and more unit test
Hi John, you have not written test for the input number greater than 100 which should return invalid value but in the above code it would return an 'A'
Hell yea IntelliJ
Great explanation! Great work!
Simple and to the point
Thank you!
That was so well described. Very very helpful. Your videos are also produced very well.
Thanks John. Another crystal clear explanation. Straight to the point 👌 💯
Thanks for your video. I almost see all your videos. So Could you make more videos like the tools, Maven, or Git, or deploy projects into AWS. Thank you so much.
15:00-16:00 wait how would 80 return a b ? When it is suppose to return a C when you set the condition to c< 81 so how would it be b?
Thank you Lex Luthor of Java language ❤️
John, this video was excellent
very clear with thinking procedures
Thank you very much for sharing this in such a clear way.
Hey John!
Thanks for your hard work! You do great job with this short explanatory videos! Create one with lambda expression please! :)
That was excellent, love your tutorials!
Awesome video! Thanks for posting!
That was very informative . Thanks for sharing your knowledge with us
Very organised and very well explained, Thank you!
Amazing!, I'm expecting the video about lambdas, pleaase!
Hey brother, your explanation is good! keep it
there's nothing QA loves more than a dev that makes sure all their unit tests are comprehensive and pass
your teaching method is good. can you do Selenium tutorial please
Wow great video, is there a second part explaining mockito?
TDD. Write the test 1st!
Great 👍🏽 introduction. Can you do advanced unit testing that involves configuration of the test class itself and adding mock beans etc before writing the actual unit tests? Thanks 🙏🏽
Clear and concise. ❤️☺️
thanks John, can you make videos of Junit with mocktio or any mocking framework
I'm loving your channel! I'm a teacher, and we do a lot of writing in the main method (at least at the beginning of the year. How would I test a certain output of the main method. And how can I test to make sure they used a print vs printf vs println in their code?
Amazing as always John!
Hey john kudo 👉 can you make a video on regular expression and lamda.
thanks John, I learned some new info from this lesson
Hi John.love your videos..you explain both concepts and code very clearly..could you please do a video around stack/queues and bfs/dfs algos? Thanks a lot :)
John! Thanks a lot!!!!
Your video was super duper helpful!
Really simple and clear for a novice!!!
Like and subscription!
What about the case :- where inside if and else block we don't have return statement and we are doing some operations.
How to test those scenarios.
Great! But I was looking for the @Before thing...