Hello guys, I am new to Kotlin. And i wanted to create an android app with a good backend in mysql. At this point what do i need to know/learn to achieve this? Thanks

Imo, Java is not great, not a little. Java is actually the very "shit that we had before Kotlin", because initially there was Java and something for enterprise in like far XX, and then it was just cheaper for enterprise. Let's be honest,the way how java does operate on the memory and other things is terrible. The world was just waiting for the age of finally good languages which a lot of people work on and it's a pleasure to use them.

I don't think lack of types is a drawback to Clojure. Maybe if you're a programmer who's used to static types, the lack of "typing" can be a big shock to the system. Clojure works in a different way so what you thought you would do with types can be achieved with multimethods and protocols. Furthermore with Clojure 1.9 you know have Clojure.Spec which allows you to specify the expected behaviour of a function with respect to the datatypes passed in or out so you get the advantages of static whilst still having dynamic typing. I say this as a current Java/Kotlin programmer who also uses Clojure. Just a different way to achieve the same objective.

I don’t wanna be that guy, but we’ve been on this Clojure discussion in #getting-started for a while now - might be worth instead @’ing someone you wanna respond to in #random or using a 🧵

Which is the correct way of documenting getter & setter separately?

var value: T
    /**
     * Returns current value.
     */
    get <-- 'redundant getter'
    /**
     * Changes value and notifies listeners. Will break current binding, if any.
     */
    set <-- 'redundant setter'

UPD: found: https://youtrack.jetbrains.com/issue/KT-17962

I have a silly question. I am trying to code a small app/script where I parse a Json and play with it. Json is very deep. in Python I can do something like pages = json["document"]["children"][0][0] Is there a way to do and simplify something like that in Kotlin, too? I am using kttp Library so I have a JSOnObject.

so you would just

json.get("document")

, etc

but you have to be explicit about your types, since java/kotlin are statically typed...

Hi, more about best practice.. when i do not need to do Utils class to hold functions now.. What is prefered way to keep those methods? You make one .kt file in project package and put all functions there?

now I’m working on a pure kotlin codebase, what should i do?

what would be the good way to implement interface that have method getName(), abstract class that implement that method, and normal class that extend abstract, and actually have specific name? Name is just string field.

how can i return a file to rest API with spring boot?

What is difference between them as follows:

val sum: Int.(Int) -> Int = { other -> plus(other) }
val sum = fun Int.(other: Int): Int = plus(other)

According to document(https://kotlinlang.org/docs/reference/lambdas.html#function-literals-with-receiver), when i use anonymous function,

The anonymous function syntax allows you to specify the receiver type of a function literal directly. This can be useful if you need to declare a variable of a function type with receiver, and to use it later.

. What does it mean? Why do i can’t use a variable of function type(not anonymous function but

val intPlus: Int.(Int) -> Int = Int::plus

) later?

Hey guys, i am exploring kotlinx form html generation. Pls.. is this still kind of life way to do it? I mean I can not find to much resources online on it..?

try:

fun isValidGender(gender: Int): Boolean {
     return gender == PetEntry.GENDER_UNKNOWN || gender == PetEntry.GENDER_MALE || gender == PetEntry.GENDER_FEMALE
 }

Hey guy Any body share me the project like the https://github.com/JetBrains/kotlinconf-app Thanks you

Guys is it a good practice to just throw all my data classes in a single file?

Your package statement must match the location of the file. If your package is "com.example.app" then your class files must be located at "com/example/app/MyClass.class" (same is recommended for .kt files).

But what is a Null

This message was deleted.

generateCmponent

does not return anything. Then look at the call-order.

generateCmponent

is called first, adding the table. After that, the body is generated. I would suggest that you return your table from the

generateCmponent

function and not append the writer.

ok i will

are there any good regex books?

filter

doesn't remove items, it creates a new list. I believe there's something like

.removeIf

I don't think there's anythin in the collection apis that operates on reference equality.

Hi, decided to get into Kotlin properly today, but I cannot get the build to work, I am not coming from a Java background so am not familiar with gradle, but it seems somewhat painful for simple things. In particular, I am getting

Could not determine Java version using executable /usr/lib/jvm/java-10-openjdk/bin/java

- not really sure how it's impossible to determine the JDK version from that. EDIT: Looks like https://github.com/gradle/kotlin-dsl/issues/816 i.e. Gradle, Kotlin and OpenJDK 10 don''t play nicely together

Thanks @marstran, but if

Unit

is the

void

equivalent, why is it assignable in kotlin but not in java?

That's the high-level explanation,

Nothing

can also be used in other ways, especially in combination with generics.

Do you have an example of how it can be used with generics? @diesieben07

Why won't it let you pass

this

?