如何解决Unable to compile class for JSP

用eclipse新搭建了一个项目，项目启动成功后报了如下错误：

type Exception report

message

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: An error occurred at line: 1 in the generated java file The type java.io.ObjectInputStream cannot be resolved. It is indirectly referenced from required .class files Stacktrace: org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:92) org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:330) org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:439) org.apache.jasper.compiler.Compiler.compile(Compiler.java:349) org.apache.jasper.compiler.Compiler.compile(Compiler.java:327) org.apache.jasper.compiler.Compiler.compile(Compiler.java:314) org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:592) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:317) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260) javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.29

 logs.

找了一圈最后发现是jar冲突。jsp-api-2.1.jar和jsp-api-2.0.jar冲突，去掉2.0重启没事。