random.javaClass.name

class MagicBox<T : Human>(vararg item: T) {
    fun <T> randomOrBackup(backup: () -> T) {
        val item = listOf(
            Boy("name", 20),
            Man("john", 35),
        )
        var random = item.random();
        println(random.javaClass.name)

//        return if (random is T) {
//            random
//        } else {
//            backup();
//        }
    }

}

open class Human(val age: Int)

class Boy(val name: String, age: Int) : Human(age)
class Man(val name: String, age: Int) : Human(age)

class Dog(val weight: Int)


fun main() {
    val box1 = MagicBox(Man("Jack", 15), Boy("张三", 16), Man("李四", 17))

   box1.randomOrBackup { Man("Jimmy", 38) }
}