Sun.misc.BASE64Encoder cannot find a solution to the jar package (Rt.jar not found)

1. Right-click Project-"Properties-" Java bulid path-"JRE System library-" Access rules-"Resolution select accessible, fill in the following * * Click OK ...

2. Base64decoder,import Sun.misc.BASE64Decoder is used when writing Java code in MyEclipse, but the eclipse tip:
Access restriction:the type Base64decoder isn't accessible due to restriction on required library C:\Program
Files\java\jre6\lib\rt.jar
Access Restriction:the Constructor Base64decoder () isn't accessible due to restriction on required library C:\Program F Iles\java\jre6\lib\rt.jar

Solution 1 (Recommended):
You only need to remove the JRE system library in Project build path, add the Library JRE system library, and it will be all right after recompiling.
Solution 2:
Errors/warnings, Compiler, Java, Preferences, Windows--
Deprecated and trstricted API, Forbidden Reference (access rules): Change to Warning