How to Kotlin - from the lead Kotlin language designer (Google I/O '18) 

​@@trollberserker1515 Yes but that class would be pretty much useless. Adding functionality would require several lines. This one-line class is completely functional in Kotlin: data class Person(val firstName: String, val lastName: String, val age: Int)

@@593jorge check out the records blogs.oracle.com/javamagazine/records-come-to-java

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@@593jorge all I hear excuses

You're so right. Java is so late.

@@chuganator ...Java the language is late, Java the JVM is still the wonder drug that it always has been. Java is dead, long live Java.

modern C# isn't far behind at all, especially when you mix in some F#

@Ahmed El Ashry , java is not dead. I said "Java is dead, long live Java", the only thing replacing Java is more Java

@Ahmed El Ashry , I've tried to escape youtube many times, but continue to fail.

yeah, I agree. He is not cocky. :D

honestly, in my experience, everyone from jetbrains seem really humble, practical, down to earth people. the corporate fakeness is completely nonexistent here. they sell their products by showing their merits, not by excessive claims or false marketing or appealing to emotions. i guess this has a lot to do with who their customers are: jetbrains sell development tools for technical people, there's a lot less room for bs here and I guess this has attracted non-bs people to their company as well

It's a presentation in front of thousands and not just a small team. And maybe he didnt have rehearsal like Google's speakers.

Yes, and maybe he's just being authentic without putting on a facade (because he doesn't need to since he is the inventor).

*modafinil intensifies*

He is doing great!!

he is not :)

Yeah I hate the name type order. Reminds be of visual basic

it's from pascal

loops and arrays declaration and not expressive though

Well most of the time you can skip those and maintain code clarity simultaneously. For eg: val obj: MyClass = MyClass() can be turned to val obj = MyClass() without losing any context of the code.

@@VivekYadav-ds8oz you can do that in java too, var obj = new MyClass(); nothing new :(

Timestamp?

@@freshfast6197 On 28:25. Yes I know I'm 2 years late.

46ģmm9bem bem j9.j

Wow that looks ugly. Is it still like that?

then use it

Why? Weren't you using Java annotations, boilerplate generators, and so on? Butterknife?

You should definitely start (perhaps start with unit tests in Kotlin). You will be thankful several years from now for learning Kotlin, trust me.

Igor Ganapolsky it's perfectly foreseeable Kotlin will die a slow death if Android apps are going the way of the dodo bird. 🐦

Kotlin is a general purpose language, not just Android. At work, we use it for backend web development

What did u do with it

Kotlin: There is!

*slams fist on table*

There has to be a better way. Sounds like Raymond Hettinger

I learned a little bit of javascript and html then thought "you know what I should do with all of my 6 hours of javascript? Try to make an app in a different language for fun!" So now I'm trying to find a tutorial

There is! Clojure!

Even for competitive programming?

Java had annotations for that, and you can and will still get a lot of null crashes now. Even more, actually, since every method where you specify an non optional parameter will crash instantly (Kotlin check) if the said parameter is null. So you need to design clearly each function param....is it optional or not, etc.

The difference is that these crashes occur at compile time and not at runtime, making you think about null safety more that when you just use annotations in java. Its about making you think in a different way about null safety.

Not if you use explicit pointers, or whatever they're called in Swift/Kotlin. If you unsafe-unwrap them, they will still crash at runtime

then why use kotlin at all if you are gonna unsafely unwrap the optionals

Downside of having too much freedom

Kotlin's semantics are not tied to the jvm, but some oop experience is helpful

right, Andrey makes you think

meow

Here is response from jetbrains team on that question: discuss.kotlinlang.org/t/best-practices-for-top-level-declarations/2198

You can return pair and it would work just like in python if i remember correctly

They are all passed by ref by design, you'd have to make a copy if you wanted to pass "by value".

@Hamad AlMarri Exact opposite, you will not want to go back to Java

IDEA from JetBrains

Continue using Java everyone else will move on and benefit from Kotlin. You are the same person from last year who thinks constant null checks are a benefit.

Hold alt & drag

www.jetbrains.com/help/rider/Multicursor.html Ctrl + up/down arrow key (win/linux) Alt + up/down arrow key (osx)

There's multiple ways: www.vojtechruzicka.com/intellij-idea-tips-tricks-multiple-cursors/

alt + vertical selection

They are very similar and for a good reason

It is actually almost 100% Scala, which also influenced Swift

Sobanya nope

I have no EXP in scala, but according to your comment you do. So lemme ask a question. I belive Java is a bit outdated langauge, my original tought was that C# will eventually take over Java's throne, but now seeing Kotlin I kinda changed my mind. However when you said that is almost 100% Scala I ahve my doubts, since up until recently I have not even heard of Scala. So someone liek you who have seen all of these languages do you think Kotlin has a shot taking over java ? I belive Java will decline in the near future eventually.

Swift is garbage.

abstractable properties + the null "?" thing don't exist in scala

Extension functions are easier to understand than type wrappers. I also like that Kotlin does NOT have implicits IMO. Kotlin has even better interop w/ Java because it uses more of the same underlying classes.

have you heard of annotations ?

Me too

😡 no fun 😡

No

Yes, because it would conflict with the syntax of a funcion with a single lambda argument

'fun' and ?: make Kotlin awesome

If you write mobile applications, there's a good chance you need to code for iOS too, which means a mac.

Of course it's IntelliJ IDEA by JetBrains: www.jetbrains.com/idea/

Watch the video

Agreed. Did we really need 'fun'?

agree

Readability doesn't mean writing lots of "public static void" or for-loop, it means that you write exactly what you mean. For example, you want to create a new list with each element is two times the element in another list. In Java, you need to do something like `List a = new List(b.size()); for (int i = 0; i < b.size(); ++i) b[i] = a[i] * 2;`. But in Kotlin you only need `val a = b.map { it * 2}.toList;`. And Kotlin version is more readable because it exactly describes what I want to do: creates a new list with each element times 2, but in Java, you need to understand the whole `new` and `for-loop` thing. For more complex logic, it's more difficult to understand what you really mean, i.e. less readability. You may say Java 8 supports lambda function and streams. Yes, Java 8 makes things better, but not good enough.

I think the real motivation of pushing kotlin so much, is because of the legal issues Android is facing against Oracle because of Java usage.

@@protaties Exactly, Java gets bloated and clunky with all the boilerplate, I'm getting into kotlin primarily because they are addressing some of the frequent annoyances that come with writing code. I mean just look at the lazy initialization example he gave, its a prime example why kotlin is great.

first++