Hello,
I found a solution on stackoverflow-- for reference I am posting that solution below... It also mentions Fred's solution but also says that that solution is more like a crack/hack- and that the recommended way to solve this problem is this--
Go to the Build Path settings in the project properties.
Remove the JRE System Library
Add it back; Select "Add Library" and select the JRE System Library. The default worked for me.
This works because you have multiple classes in different jar files. Removing and re-adding the jre lib will make the right classes be first. If you want a fundamental solution make sure you exclude the jar files with the same classes.
Reference-->
http://stackoverflow.com/questions/860187/access-restriction-on-class-due-to-restriction-on-required-library-rt-jar
Sincerely,
Arvind.