Unfortunately, if a future API revision lets you add elements of types other than JMenu to a JMenuBar, it will no longer be necessary, or even safe, to cast the returned elements to JMenu.
不幸的是，如果将来的API修订版允许将除jmenu类型之外的元素添加到JMenuBar，就不再需要把返回的元素强制转换JMenu了。
Unfortunately, if a future API revision lets you add elements of types other than JMenu to a JMenuBar, it will no longer be necessary, or even safe, to cast the returned elements to JMenu.
不幸的是，如果将来的API修订版允许将除jmenu类型之外的元素添加到JMenuBar，就不再需要把返回的元素强制转换JMenu了。
应用推荐