今天在切换java 1.8的时候遇到了问题，本来按照常规，方法很简单就解决了，可以后来折腾半小时。
项目因为需要切换至：1.8
问题描述： 项目右键-》Properties-》MyEclipse-》Project Facets -》java 1.8，切换时，
报错：Reason: Failed while changing version of java to 1.8
解决方案： 找到项目工作空间 F:/xxx -》找到项目里的 .settings文件-》打开后找到org.eclipse.wst.common.project.facet.core.xml打开
修改<installed facet="java" version="1.8"/> 的 version="";属性。
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