Is `javaClass` equal to `SomeClass::class.java`?

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[ziggy42]

Is javaClass equal to SomeClass::class.java?

[Adrian M]

javaClass refers to SomeClass.Companion and not to SomeClass

[ziggy42]

Mmm what is SomeClass.Companion?

[ziggy42]

If I don't have a companion object in SomeClass?

[Adrian M]

https://kotlinlang.org/docs/reference/object-declarations.html#companion-objects

[Adrian M]

If you don't have a companion object in the class, then javaClass call won't compile

[ziggy42]

I have a springboot RestController, without companion object, and IntelliJ doesn't tell me anything if I try to use javaClass

[ziggy42]

private val LOGGER = Logger.getLogger(javaClass)

[Adrian M]

This is interesting. If you want to access .javaClass like this: SomeClass.javaClass, then it won't compile without a companion object.
But if you want to do it directly from the class, then it compiles and javaClass == SomeClass::class.java is true

[Adrian M]

let's wait for someone with more knowledge about it, I'm really curious now 🙂

[hho]

javaClass has nothing to do with companion objects. It just needs an instance, it's an equivalent to Java's .getClass().

[hho]

Java's String.class is String::class.java
Java's "abc".getClass() is "abc".javaClass

[hho]

(roughly)

[karelpeeters]

But then String.javaClass would be the companion object's class if String had one.

[karelpeeters]

I think that's what he was saying.

[hho]

ah, I didn't get that

[ziggy42]

That's a bit confusing honestly

[ziggy42]

What do you think would be the most elegant way to say private val LOGGER = Logger.getLogger(javaClass), without having to worry if I have a companion object in the class or not?

[karelpeeters]

If you're already in a class instance javaclass will always be the right one.

[ziggy42]

Perfect, thank you!

[karelpeeters]

It's just that MyClass.javaClass can be the companion class, or it can be a compiler error.