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<@U0ANUS2BA> i saw an answer to a question you provided on SO and just wanted to get some more information. It's about retaining parameter names on constructors

Was hoping you could shed some light on it for me

if you have a moment :slightly_smiling_face:

Thanks for such quick reply :slightly_smiling_face: The question I saw your answer on is here: <https://stackoverflow.com/questions/36093019/does-kotlin-compiler-always-retain-parameter-names-in-bytecode> it was a while ago

but to boil down the issue I am noticing in IntelliJ that the parameter names are NOT retained

at some point the parameter names are lost on a data class constructor

I'm stepping through the spring-data-mongodb code

and i see params being named arg0.....argXX

if I clean and re-build ... parameter names come back

then at some point (hard to pin-point when exactly) they're gone

where do you see that — in the IntelliJ decompiler, in the `javap` bytecode output, in the Kotlin bytecode toolwindow, in Kotlin reflection, in Java reflection, … ?

as I am stepping through the java code of spring-data-mongo...the code is looking at the constructor of a data class...I am seeing it while stepping through in IntelliJ

spring-data-mongodb code is in Java ... the class that it's looking at is in Kotlin

OK, so the StackOverflow link above is irrelevant here because it’s only related to the parameters that are introspected via Kotlin reflection at runtime (`KParameter.name`)

here you should pass the `-java-parameters` command line argument to Kotlin

oh ... I will read the docs on that param ... but does it force preservation of param names?

I was not aware of that option ... will try it and read the docs on it

there’s no docs unfortunately yet, only `kotlinc -help`. The `-java-parameters` is basically equivalent to javac’s `-parameters`.

alright I will check it out ... thanks so much for your help .... I should be able to apply it in the kotlinOptions { ... } `build.gradle` block as well, right?

btw I found some docs here, see `javaParameters`: <https://kotlinlang.org/docs/reference/using-gradle.html#attributes-specific-for-jvm>

haha I just found it too ... `Generate metadata for Java 1.8 reflection on method parameters` that's good enough docs for me

Just need to know when to look! Thank you for pointing it out for me. OGROMNOE SPASIBO!