Access restriction: The type Unsafe is not accessible due to restriction on required library

無事下載Google的common包guarva玩玩，丟到eclipse中就編譯報錯：Access restriction: The type Unsafe is not accessible due to restriction on required library C:\Java\jre6\lib\rt.jar

問題原因：Eclipse 默認把這些受訪問限制的API設成了ERROR。

解決辦法：將Windows->Preferences->Java-Complicer->Errors/Warnings->Deprecated and restricted API，中的Forbidden references(access rules)設置爲Warning，即可以編譯通過。