用jarslink做module隔离时,dubbo调用会抛ClassNotFoundException.经查是ClassLoader不一致.

```
    public static Class<?> getReturnType(Invocation invocation) {
        try {
            if (invocation != null && invocation.getInvoker() != null
                    && invocation.getInvoker().getUrl() != null
                    && !invocation.getMethodName().startsWith("$")) {
                String service = invocation.getInvoker().getUrl().getServiceInterface();
                if (service != null && service.length() > 0) {
                    Class<?> cls = ReflectUtils.forName(service);
                    Method method = cls.getMethod(invocation.getMethodName(), invocation.getParameterTypes());
                    if (method.getReturnType() == void.class) {
                        return null;
                    }
                    return method.getReturnType();
                }
            }
        } catch (Throwable t) {
            logger.warn(t.getMessage(), t);
        }
        return null;
    }
```
if (actualArgType instanceof ParameterizedType) {
                                returnType = (Class<?>) ((ParameterizedType) actualArgType).getRawType();
                                genericReturnType = actualArgType;
                            } else {
                                returnType = (Class<?>) actualArgType;
                                genericReturnType = returnType;
                            }
                        } else {
                            returnType = null;
                            genericReturnType = null;
                        }
                    }
                    return new Type[]{returnType, genericReturnType};
                }
            }
        } catch (Throwable t) {
            logger.warn(t.getMessage(), t);
        }
        return null;
    }
    public static Long getInvocationId(Invocation inv) {
        String id = inv.getAttachment(Constants.ID_KEY);
        return id == null ? null : new Long(id);
    }
    /**
     * Idempotent operation: invocation id will be added in async operation by default
     *
     * @param url
     * @param inv
     */