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Can someone point me to a documentation where it is defined how the class name is derived from the kotlin file name. So e.g. you have the file code.kt and than there will be internally a class generated that is called: CodeKt

Hmm i just realize that it really depends on many things. What i want to do is find all toplevel functions via reflection in one file. Maybe there is an other way without knowing the internal class name to do this.

The file -&gt; class conversion happens <https://github.com/JetBrains/kotlin/blob/c1a1b5a81d1deefc7e96dd344a491c3fc86a4e9e/compiler/ir/backend.jvm/lower/src/org/jetbrains/kotlin/backend/jvm/lower/FileClassLowering.kt#L82|here>
<https://github.com/JetBrains/kotlin/blob/232184047b2a47e08f7ee89e87505dac49d1169a/compiler/frontend.common.jvm/src/org/jetbrains/kotlin/load/kotlin/PackagePartClassUtils.kt#L50|Here> and <https://github.com/JetBrains/kotlin/blob/cb4fb15093d509aec1708ad8674bcb278eb79e5a/core/compiler.common/src/org/jetbrains/kotlin/name/NameUtils.kt#L35|here> an actual implementation of the name conversion if `@JvmName` annotation is not defined

Ok i see. It really gets compilcated :smile:
But thank you very much for this fast response. I will look into it.
At the end i want to collect functions with a specific Annotation. I am only interested in toplevel functions. But i need to do this for files which are compiled during runtime of the application. So i need to load the class dynamically.

Well, it depends on inputs you have
If you already have some `Class<*>` and want to understand if it is a "class for kotlin file", you can rely on the following invariant:
• ~class is `final`~
• ~it doesn't contain `@kotlin.Metadata` annotation~
• ~it contains only `static` functions/fields~
• ~functions are annotated with `@kotlin.Metadata`~


But if you want to scan the classpath to find such classes, it's more complicated
They easiest way is to load all and check each one for the invariant above
Also you potentially can use `kotlinx-metadata-jvm` library, but I'm not sure about exact API which will help you

> If you already have some `Class<*>` and want to understand if it is a "class for kotlin file", you can rely on the following invariant
The correct way in this case would be to read `@kotlin.Metadata` annotation on the class, and check its `Metadata.kind` value (see the <https://github.com/JetBrains/kotlin/blob/2adf39a10ffb9fa46827f66427b831c559a481c1/libraries/stdlib/jvm/runtime/kotlin/Metadata.kt#L28|kdoc>).

But the problem for me is that the file is not loaded by the classloader. Because i compile it during runtime.
But yea so i can use this function to get the classname. (Of course i need also search inside of the file for the @JvmName annotation and use this if it exists) right?
```PackagePartClassUtils.getPackagePartFqName(FqName("package name when exists"), kotlinFile.name)```

For my usecase it is enough when i know the class name to be able to load it and check for member functions with a special annotation.