Using Java LambdaMetafactory to convert Kotlin property to lambda without reflections and faster

Example.kt

// Please note that you don't even need kotlin-reflect.jar

class C {
    val f: String
        get() = "ok"
}

fun usage() {
    val fn = makeFunction(C::f)
    println(fn(C()))
}

LambdaMetafactory.kt

inline fun <reified Owner, reified Value> makeFunction(property: KProperty1<Owner, Value>): (Owner) -> Value {
    val propertyGetter = getterMethod(Owner::class, property)
    val lookup = MethodHandles.lookup()!!
    val targetMethod = lookup.unreflect(propertyGetter)

    return makeFunctionImpl(lookup, targetMethod, Value::class.java, Owner::class.java)
}

@PublishedApi
internal fun <Owner, Value> makeFunctionImpl(
    lookup: MethodHandles.Lookup,
    targetMethod: MethodHandle?,
    valueJavaClass: Class<Value>,
    ownerJavaClass: Class<Owner>
): (Owner) -> Value {
    val factory = LambdaMetafactory.metafactory(
        lookup,
        Function1<*, *>::invoke.name,
        MethodType.methodType(Function1::class.java),
        MethodType.methodType(Any::class.java, Any::class.java),
        targetMethod,
        MethodType.methodType(valueJavaClass, ownerJavaClass)
    )

    @Suppress("UNCHECKED_CAST")
    return factory.target.invoke() as Function1<Owner, Value>
}

@PublishedApi
internal fun getterMethod(clazz: KClass<*>, property: KProperty1<*, *>): Method =
    clazz.java.getMethod("get" + property.name[0].titlecase(Locale.ENGLISH) + property.name.drop(1))

simple-comparion.kt

@OptIn(ExperimentalTime::class)
fun main() {
    val count = 1000000000
    val fn = makeFunction(C::f)
    val instance = C()
    val method = getterMethod(C::class, C::f)

    println("Lambda")
    var total = 0L

    measureTime {
        repeat(count) {
            total += fn(instance).length
        }
    }.let {
        println("Lambda $it") // 37 millis
    }

    println("Reflections")
    measureTime {
        repeat(count) {
            total += (method.invoke(instance) as String).length
        }
    }.let {
        println("Reflections $it")  // 3.9 seconds
    }

    println("Done")
}