Eclipse下BASE64Decoder提示錯誤的解決辦法

在MyEclipse中編寫Java代碼時，用到了BASE64Decoder，import sun.misc.BASE64Decoder;但是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）：
只須要在project build path中先移除JRE System Library，再添加庫JRE System Library，從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