eclipse "link search complete"

When I click on the hyperlinked ClassCastException, I get a dialog with the
 following:
- Title: "Problem Occurred"
- Message: "link search complete"
- Reason: "Check the details"
- Details: "Error"

原因：在安装目录多了个linksBak文件夹（自己添加的，用来备份links下的文件），删掉该文件夹重启eclipse解决。