import java.lang.reflect.InvocationHandler
import java.lang.reflect.Method
import java.lang.reflect.Proxy

interface Hello {
    fun hello()
}

class HelloImpl: Hello {
    override fun hello() {
        println("Hello world")
    }
}

class MyInvocationHandler(private val target: Any): InvocationHandler {

    override fun invoke(proxy: Any, method: Method, args: Array<out Any>?): Any? {
        println("Invoking sayHello")
        return method.invoke(target)
    }
}

fun main() {
    val hello = HelloImpl()
    val handler = MyInvocationHandler(hello)
    val proxy = Proxy.newProxyInstance(HelloImpl::class.java.classLoader, HelloImpl::class.java.interfaces, handler) as Hello
    proxy.hello()
}