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Learner Reviews & Feedback for Kotlin for Java Developers by JetBrains

1,919 ratings

About the Course

The Kotlin programming language is a modern language that gives you more power for your everyday tasks. Kotlin is concise, safe, pragmatic, and focused on interoperability with Java code. It can be used almost everywhere Java is used today: for server-side development, Android apps, and much more. Kotlin is 100% compatible with all existing Java frameworks, and has good tooling support. It’s a pragmatic language with a very low learning curve, and can be quickly grasped by Java developers. Kotlin code might be compiled not only to JVM bytecode but to JavaScript and Native code as well, but this course is focused on Kotlin/JVM. This course aims to share with you the power and the beauty of Kotlin. We'll have a basic overview of the language, as well as a discussion of many corner cases, especially concerning Java interoperability. The course is based on your Java experience; it shows the similarities between the two languages and focuses on what's going to be different. Note that this course won't cover the programming fundamentals. We'll discuss: basic syntax, nullability, functional programming with Kotlin, object-oriented programming with Kotlin, the power of the Kotlin standard library, and Java interoperability....

Top reviews


Jun 28, 2019

Excellent course, packed with relevant content and useful hands on Kotlin exercises with great feedback based on Coursera provided unit tests. Looking forward to more Coursera courses from JetBrains.


Feb 10, 2019

This course is a very comprehensive and detailed introduction to Kotlin. However, it would be even better if it could include the generics part which is the most difficult but quite frequently used.

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351 - 375 of 469 Reviews for Kotlin for Java Developers

By Mykhailo V

Jan 12, 2020


By Andrii V

Jan 18, 2019


By Arman Z

Jul 22, 2021


By Michael S

Mar 13, 2021

I enjoyed this course. It gives a pretty good view into the more useful parts of the language and definitely makes a great case for a Java developer to become a Kotlin convert. My only complaints about this course are in regard to the GameOfFifteen assignment. The README on what they are looking for points to a web version of the game and basically says to implement an isEven function to check if a permutation is solvable and then implement the game interface to get everything working. The problem is this: I implemented my game just the way the web game works - specifically, my game chose a random cell to be the empty cell upon initialization, just as the web game did. I also set up my "hasWon" state to be the case where the numbers are in order AND the empty cell is in the bottom-right position, just as the web game seemed to be showing. When I ran the tests on my project, they failed. I had to do a debug deep dive to find that the tests are expecting that hasWon can be true regardless of the position of the empty cell, as long as the numbers are in order and to find that the tests expect the game to always initialize with the empty cell in the bottom-right position. It was easy enough to fix my game to match their tests rather than the example game, but I lost some time unnecessarily to this. It would probably be helpful to others who take this course if a couple simple notes in the README were added to indicate that the game should initialize with the empty cell in the bottom-right position and that the game is won if the cells are in ascending numerical order regardless of the position of the empty cell.

By Alexander T

Aug 23, 2022

Course is an awesome starter for a deep dive into kotlin. Lectures material is great. Assignments could be improved though. Descriptions of certain tasks was a bit cryptic. I had to analyze test cases to figure out what actually needs to be implemented and those tests cases are not complete either had to add more when intergation ones failed.

Here is an example of what I mean from the last week assignment: "The board for the game of Fifteen is filled randomly with numbers from 1 to 15 and one empty space. " Here sounds like word "randomly" also relates to the empty space e.g. we should put space at random possition between permutations. This is exactly what I did, I also played the actual game implementation provided and it works the same way e.g. when you shuffle space is at random position. So my implementation seems correct, but all the tests fail. Why? Because in all the scenarious there is an assumtion that empty cell is always the last one so I had to rewrite the logic to match tests.

By Stephen P

Jul 17, 2021

Overall, great course that accomplishes what it promises. I learned how to develop in Kotlin relying on already knowing Java. Pros: The videos are clear and concise, with high "signal-to-noise ratio". Tests during the videos were on point and exposed common misconceptions people commonly have when learning Kotlin. The solution videos after completing the weekly projects were helpful in making working code more efficient and readable. Cons: The instructions for Week 3 incorrectly specified what was required, leading me on a wild goose chase for several hours. There were only solution videos for weeks 1 to 3. It appears nobody monitors the discussion forums anymore. There's questions asked 2 years ago with many "me too"s, but no response from staff.

By Josep G F

Nov 22, 2020

I liked this course but to be honest, I found that the assignments were a little difficult to understand due to the concepts they were related with. The last assignment related to the Fifteen game, it was a little complicated to understand how to get the parity of a permutation. Situations like this made the exercise a little frustating because I understood the Kotlin concepts but it wasn't enough to finish the assignments. Probably like in the real life problems :)

Just wanted to let you know, just in case can help in some way to improve the way how the assignments are provided. Maybe explain a little further about some extra concepts or something else.

Thank you for this great course!

By Ivar N

Jul 17, 2022

First couple of modules are very good but then it feels like the narrator gets a bit bored with it all and the assignments shift focus more towards algorithms than actually tackling Kotlin syntax and language features. I get that it's more fun to create assignments for making games etc but focus should be on learning the language and not figuring out how to multiply rational numbers or what the parity of a permutation is (I'm stll not sure). At least having access to prewritten unit tests for the assignments help a lot and the course is fairly inexpensive so overall I'd still recommend it.

By Alexander L

Oct 30, 2018

In terms of provided content this course is great. Provided knowledge is definitely useful for almost any Java developer. Content is greatly structured, assigments are pretty cool.

Hovewer, there is some problems with presenting and plaform: Sometimes speaker is too slow (My usual speed on this course is 1.75x) and mumble. Subtitles also not helping (at least in weeks 4-5 when I listening them). Kotlin Playground can be marked as completed only on second attempt for some reason.

Problems are not critical, so I still recomend this course.

By Mohammed S

Feb 4, 2022

This course was excellent with one shortcoming which I'll describe later.

The explainations and use cases for each features given is precise and very helpful. Coding examples are clear and helpful. Only thing I hated are assignments. Instead of using real world examples, they were all focused on Maths. It would be better if you use practical examples used in daily life/work. Still overall a must course for beginners in Kotlin. Am looking forward to course explaining advanced Kotlin features like coroutines.

By Pablo V

Dec 2, 2018

The course was very interesting, however, I have to say that most of the knowledge I gained it in other places like stackoverflow website. I also consider that the course was a bit hard to catch if you are not practicing Kotlin day to day. I have been studying Kotlin as an Android developer for about 3 months and some stuff were difficult to understand, I guess a person with zero experience would have pulled his hair out. As another feedback, I would have liked being more close with the staff.

By Adedimeji S

Jun 3, 2020

The course was well delivered and filled with useful tasks and assignments which really helped drive home the concepts being taught. Most importantly, I've gone from being unsure about how to handle the sheer amount of differences between Kotlin and Java to being comfortable using Kotlin and willing to explore more of its features. The only drawback from the course delivery was the slight difficulties in understanding the presenter, but those were largely minimal issues.

By Dmitry S

Apr 12, 2021

I'd rate that high because of it's assignment system. If you pass the tests provided by the edutools plugin, you are pretty sure, you will submit. This also gives a much deeper insight on the corner cases for your algorithm.

The last assignment GameOf15 was a bit tricky though. I am specifically referring to canMove method - it's not clear at all from the task, how to implement or why would you even need that - so I just made it return true all the time

By Dave G

Feb 24, 2021

the videos interspersed with quizzes are a really good way to learn. The challenges are really good, but it would be nice to see video solutions for the final ones. The descriptions of some of the tasks need some work - there are plenty of suggestions in the forum so I won't add any more here. The video content is excellently presented and well paced. Display on a mobile device with a small screen is a bit lame, especially for the (later) playgrounds.

By umberto a

Nov 23, 2021

Course is too much difficult. Assignement times for exercises are not real. I spent triple time to do that. I think that it is an advanced course and not not a beginner/medium as they say. I'm a java android developer, and do not use lambda expressions or functional programming that is required to know. Anyway it gives the basics of Kotlin going to dig the examples. Teachers are very professional and skilled.

By Ignazio C

Dec 11, 2020

The content of the course is definitely valid. It gives a nice overview of the Kotlin language. The title is "for Java developers" but only a basic knowledge of java is required. The only slightly negative aspect are on my opinion the assignments: sometime are not clear enough and the ones for week4 and week5 could have been easier with a different object definition

By Yanbo H

Apr 28, 2020

It's a pretty nice course for people who have already know some object-oriented programming languages.

You can quickly understand what is the new features compared with Java and why Kotlin was designed like this way. The thing I like most is that it showed what is compiled in the bytecode level, which helped me a lot in understanding what is going on under the hood.

By Wan Y

Jul 18, 2021

A very pragmatic course for those who have some experience in Java. This course covers several important features of Kotlin, alongside some high quality assignments to test your understanding. The only downside is that the lecturer speaks too fast sometimes and the subtitle is far from accurate. For non-native speakers, it might take some time to get accustomed to.

By Slava K

Nov 5, 2020

The course covers most of the important topics and gets into advanced areas of knowledge.Most of them are well explained with very good examples.As other stated, I think many of the home assignments miss the point of practicing Kotlin topic by concentrating on algorithmic issues, I would change them to be more like the playground tasks.

By Robert G

Jun 22, 2019

Great course, great structure + exercises.

Minor thing: The English needs some improvement - it's quite hard to follow sometimes, and sometimes even the transcript fails (I read "[unintelligible]" one time).

So much new stuff... but you managed to get this into this short course, and even I took something away from it - kudos!

By Michael O

Aug 26, 2020

Sometimes difficult to understand instructor, but that is as much me as the course. Some of the examples are not left on the screen long enough to digest, or even long enough to realize I need to pause the video in order to examine them thoroughly, before moving on to the next thing. Requires annoying moving around the video.

By Adil S

Sep 7, 2020

Great for beginners.. Some things that can be improved

1) The compiler used to check the test assignments need to be upto date. Personally I had to change the code multiple times and resubmit it since I was working with Kotlin 1.4 and the compiler used to run and check the test in coursera was of a lower version.

By Catalin D

Mar 4, 2020

Sometimes it is hard to understand what she is saying and the subtitles are not very accurate. Very informative and great course for introducing any java dev to Kotlin. Thank you! P.S. the last assignment could really use some better tests and specification (the first one was quite ambiguous)

By Robert F

Dec 9, 2018

This course allows getting familiar with basic constructions and ideas included in Kotlin. The material is easy to understand and clearly presented.

I gave only 4 stars because some assignments force you to focus on a domain of exercise instead of practicing the language itself.

By Chintan P

Apr 21, 2020

The course was amazing. It covered almost all the concepts.

But sometimes I felt the course was in speed. like it covered so many things in one video which I got some trouble.

The rest was good.

Thankyou Jetbrains and Coursera for such an amazing course.