Description Resource Path Location Type
A cycle was detected in the build path of project 'shgl-category-api'. The cycle consists of projects {shgl-category-api, shgl-category-provider} shgl-category-api Build path Build Path Problem
项目出现红色叹号 有可能好几种原因：
先把eclipse转换到Markers视图，windows---->show view ---->markers ，查看具体错误信息。
1、项目右键 属性 java build path 点选library选项卡 更改jre system library为你本地的jre 或者jdk
2、多个项目项目循环引用，导致的，“A cycle was detected in the build path of project: XXX”
解决方法非常简单：
Eclipse Menu -> Window -> Preferences... -> Java ->Compiler -> Building -> Building path problems -> Circular dependencies -> 将Error改成Warning
3、the project cannot be built until its prerequisite问题.解决方法.
把项目 close一下.再open, project->clean就可以了
转自：http://blog.csdn.net/chenyulancn/article/details/44237641