x.x.x.xxResponse cannot be cast to x.x.x.xxResponse 异常可能原因

[xcorpio]

• I have searched the issues of this repository and believe that this is not a duplicate.
• I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

• Dubbo version: 2.7.4.1
• Operating System version: macos, linux
• Java version: 1.8

背景

这个issue不是正常的使用场景下产生的啊... 我在做一个 dubbo 的压测工具 , 要在 JVM 不退出的情况下 重载 dubbo 的接口class. 如: GreetingService

public interface GreetingService {
  String sayHello(String name);
  HelloResponse sayHello2(String name);
}

现象

第一次调用时 HelloResponse 返回正常，类加载器是: pea.app.compiler.ReloadableClassLoader
(这个是我自定义的类加载器, 每次调用都会是新的)。

之后的调用就会报异常:

[error] p.d.a.DubboAction - failure: ==========> java.lang.ClassCastException: pea.example.ext.dubbo.response.HelloResponse cannot be cast to pea.example.ext.dubbo.response.HelloResponse
	at org.apache.dubbo.common.bytecode.proxy1.sayHello2(proxy1.java)
	at pea.example.dubbo.GreetingSimulation.$anonfun$scn$1(GreetingSimulation.scala:23)
	at pea.dubbo.action.DubboAction.$anonfun$execute$1(DubboAction.scala:43)
	at scala.concurrent.Future$.$anonfun$apply$1(Future.scala:658)
	at scala.util.Success.$anonfun$map$1(Try.scala:255)
	at scala.util.Success.map(Try.scala:213)

问题

这个问题大概是怎么产生的啊？为啥第一调用没事, 代理类返回的 HelloResponse是不是有缓存啊之类的？如果有怎么清掉？

[CrazyHZM]

Try it with the latest version, if you still have problems, you can reopen the issues