The type ProxyGenerator is not accessible due to restriction on required library问题的解决

怎样解决类似的问题：

　　Multiple markers at this line-Access restriction: The type ProxyGenerator is not accessible due to restriction on required library D:\java\MyEclipse\Common\binary\com.sun.java.jdk.win32.x86_64_1.6.0.013\jre\lib\rt.jar- Access restriction: The method generateProxyClass(String, Class[]) from the type ProxyGenerator is not accessible due to restriction on required library D:\java\MyEclipse\Common\binary\com.sun.java.jdk.win32.x86_64_1.6.0.013\jre\lib\rt.jar

原因：

Eclipse 默认把这些受访问限制的API设成了ERROR。

解决方法：
Windows -> Preferences -> Java -> Compiler -> Errors/Warnings -> Deprecated and trstricted API -> Forbidden reference (access rules): -> change to warning