【发布时间】：2017-03-15 13:19:52
【问题描述】：
我正在开发一个由我之前的人主要用 jsp 编写的 Web 应用程序。一切都运行良好，但是突然当我尝试在服务器上运行项目（来自 Eclipse）时，我在浏览器和 Eclipse 中收到以下两个错误：
HTTP Status 500 - Unable to compile class for JSP
type Exception report
message Unable to compile class for JSP
description The server encountered an internal error that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: Unable to compile class for JSP
org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:84)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:328)
org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:409)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:288)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:267)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:255)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:563)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:293)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
当我刷新浏览器时，我得到一个不同的错误。
HTTP Status 500 - Unable to load class for JSP
type Exception report
message Unable to load class for JSP
description The server encountered an internal error that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: Unable to load class for JSP
org.apache.jasper.JspCompilationContext.load(JspCompilationContext.java:598)
org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:137)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:305)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
java.lang.ClassNotFoundException: org.apache.jsp.automation.actions.index_jsp
java.net.URLClassLoader$1.run(URLClassLoader.java:366)
java.net.URLClassLoader$1.run(URLClassLoader.java:355)
java.security.AccessController.doPrivileged(Native Method)
java.net.URLClassLoader.findClass(URLClassLoader.java:354)
org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:133)
org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:65)
org.apache.jasper.JspCompilationContext.load(JspCompilationContext.java:596)
org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:137)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:305)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
我在很多地方读到错误是由于tomcat没有指向正确的jdk，我已经这样做了。它指向 Java 1.7。如果我指向 1.8，我会收到 The type java.lang.CharSequence cannot be resolved. It is indirectly referenced from required .class files 错误。
之前的代码运行良好，但我不确定到底发生了什么。我过去也遇到过这个错误，我曾经重新导入项目等来解决它。这一次我真的很想找到它的根源，因为这似乎偶尔会发生。我确定这是我缺少的一些配置，但我不确定是什么。
【问题讨论】：
-
有人能解释一下为什么他们投票反对吗？