HttpServlet cannot be resolved to a type
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Description Resource Path Location Type
HttpServlet cannot be resolved to a type SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 15 Java Problem
HttpServletRequest cannot be resolved to a type SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 22 Java Problem
HttpServletResponse cannot be resolved to a type SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 22 Java Problem
ServletException cannot be resolved to a type SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 22 Java Problem
The import javax.servlet cannot be resolved SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 5 Java Problem
The import javax.servlet cannot be resolved SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 6 Java Problem
The import javax.servlet cannot be resolved SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 7 Java Problem
The import javax.servlet cannot be resolved SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 8 Java Problem
The import javax.servlet cannot be resolved SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 9 Java Problem
HttpServlet cannot be resolved to a type SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 15 Java Problem
HttpServletRequest cannot be resolved to a type SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 22 Java Problem
HttpServletResponse cannot be resolved to a type SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 22 Java Problem
ServletException cannot be resolved to a type SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 22 Java Problem
The import javax.servlet cannot be resolved SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 5 Java Problem
The import javax.servlet cannot be resolved SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 6 Java Problem
The import javax.servlet cannot be resolved SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 7 Java Problem
The import javax.servlet cannot be resolved SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 8 Java Problem
The import javax.servlet cannot be resolved SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 9 Java Problem
WebServlet cannot be resolved to a type SimpleServlet.java /JavaHelloWorldApp/src/main/java/wasdev/sample/servlet line 14 Java Problem
在文章 Java中REST API使用示例——基于云平台+云服务打造自己的在线翻译工具 中从IBM Bluemix上下载的Java示例代码，导入到Eclipse之后，出现以上错误信息！
错误原因：
Eclipse是刚刚安装的，还没有配置服务器运行环境！
解决办法：
1、首先要安装一下Tomcat；
通常是下载一个zip压缩包，解压一下就可以了；
2、Eclipse中点击Window菜单，选择Preferences
3、在左侧展开Server，选择Runtime Environment，右侧点击Add按钮
4、在弹出的窗口中选择你的Tomcat版本
5、点击“Browse”按钮选择Tomcat的安装位置，选择合适的JRE版本，点击Finish按钮完成。
通过上面的步骤，上面的错误都全部解决了，如果你的项目还显示 有错误，就需要考虑其它原因了。
可以参考：xxx cannot be resolved to a type 错误解决方法