在MyEclipse中編寫Java程式碼時，用到了BASE64Decoder，import sun.misc.BASE64Decoder；可是Eclipse提示： 
Access restriction: The type BASE64Decoder is not accessible due to restriction on required library C:\Program 
files\java\jre6\lib\rt.jar 
Access restriction : The constructor BASE64Decoder() is not accessible due to restriction on required library C:\Program files\java\jre6\lib\rt.jar 

解決方案1（推薦）： 
只需要在project build path中先移除JRE System Library，再新增庫JRE System Library，重新編譯後就一切正常了。 
解決方案2： 
Windows -> Preferences -> Java -> Compiler -> Errors/Warnings -> 
Deprecated and trstricted API -> Forbidden reference (access rules): -> change to warning