程序代码：

HTTP Status 500 - An exception occurred processing JSP page /index.jsp at line 100

type Exception report

message An exception occurred processing JSP page /index.jsp at line 100

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: An exception occurred processing JSP page /index.jsp at line 100

97:     <%
98:         int t1;
99:         int t2;
100:         count_num co1 = new count_num();
101:         t1 = co1.count("recent");
102:         count_num co2 = new count_num();
103:         t2 = co2.count("hire");


Stacktrace:
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:568)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:455)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)

root cause

javax.servlet.ServletException: java.lang.UnsupportedClassVersionError: count/count_num
    org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:916)
    org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:845)
    org.apache.jsp.index_jsp._jspService(index_jsp.java:408)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)

root cause

java.lang.UnsupportedClassVersionError: count/count_num
    org.apache.jsp.index_jsp._jspService(index_jsp.java:169)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)

note The full stack trace of the root cause is available in the Apache Tomcat/7.0.55 logs.
Apache Tomcat/7.0.55

这是我程序的错误信息，我已经把我自己写的类打包成jar包放在lib下了，可是为什么还是有错误？谢谢各位过路大神