exception:
org.apache.jasper.JasperException: Unable to compile class for JSP:
An error occurred at line: 152 in the jsp file: /user.jsp The type java.lang.CharSequence cannot be resolved. It is indirectly referenced from required .class files
 149:       int length=5;
    150:         for (int i = 0; i <= length; i++ ) {  
    151:             int pos = rand.nextInt(charset1.length()); 
    152:             sb.append(charset1.charAt(pos));  
    153:         }
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:423)
                    org.apache.jasper.compiler.Compiler.compile(Compiler.java:308)
                    org.apache.jasper.compiler.Compiler.compile(Compiler.java:286)
                   org.apache.jasper.compiler.Compiler.compile(Compiler.java:273)
        org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:566)
      org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:317)
         org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
                org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
                     javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.14 logs.