1.Java compiler level does not match the version of the installed Java project facet，意思是jdk版本和project facet版本不一致
2.解决Java Compiler和Project facets的版本需一致
eclipse中，项目有红叉之-Java compiler level does not match the version of the installed Java project facet.
原文：http://www.cnblogs.com/-scl/p/7551200.html