Access restriction:The type XXXX is not accessible

报错： Access restriction:The type XXXXis not accessible due to restriction on required library C:/Prog

报错： 
Access restriction:The type XXXX is not accessible due to restriction on required library C:/Program Files/Java/jre7/lib/rt.jar 
  
解决方法： 
Project -> Properties -> libraries， 
先remove掉JRE System Library，然后再Add Library重新加入。