Java泛型扩展列表

Question

我有以下课程：

public interface ServiceSynchronizableEntity {
    ....
}

public class BaseListResponse<T> {
    ....
}

public class BaseSynchronizableListResponse<T extends ServiceSynchronizableEntity> extends BaseListResponse<T> {
    ....
}

public class MySecondClass implements ServiceSynchronizableEntity {
    ....
}

public class MyFirstClass extends BaseSynchronizableListResponse<MySecondClass> {
    ....
}

public class What<S extends BaseSynchronizableListResponse<ServiceSynchronizableEntity>> {

}

然后我将其用作：

What what = new What<MyFirstClass>();

当我想使用MyFirstClass作为扩展BaseListResponse<ServiceSynchronizableEntity>>的类型参数时，它向我显示

Main.java:26: error: type argument MyFirstClass is not within bounds of type-variable S
    What what = new What<MyFirstClass>();
                         ^
where S is a type-variable: S extends BaseSynchronizableListResponse<ServiceSynchronizableEntity> declared in class What

怎么了？

编辑：缺少一堂课。 查看： http : //ideone.com/D4snKP

谢谢！

Answer 1

我以前发布（现在已删除）的解决方案类似，因为它需要更改通用签名。

重要的变化来自：

class What<S extends BaseSynchronizableListResponse<ServiceSynchronizableEntity>> {}

至：

class What<S extends BaseSynchronizableListResponse<? extends ServiceSynchronizableEntity>> {}

参见http://ideone.com/wyXvcl以获取固定版本