继承JFrame出错哦,下面是显示的错误的信息:Access restriction: The type JFrame is not accessible due to restriction on required library D:\Program Files\Java\jdk1.8.0_40\jre\lib\rt.jar解决办法:右键工程目录选择properties 选择java build path ->libraries ->JRE System Library->Edit->Alternate JRE ...【阅读全文】