project---->properties--->Libraries--->JRE System
Library--->Access rules--->Edit--->Add--->Rule Paern
写上**
或者
1. Open project properties.
2. Select Java Build Path node.
3. Select Libraries tab.
4. Remove JRE System Library.
5. Add Library JRE System Library.
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原文：http://www.cnblogs.com/MyBeN/p/3769946.html