各位，这是啥错误？快帮帮忙

Question

23:13:20,825 DEBUG [yysoft.util.Debug] Received throwable with Message: org/jfree/chart/axis/DateAxis
23:13:20,825 DEBUG [yysoft.util.Debug] 
javax.servlet.ServletException: org/jfree/chart/axis/DateAxis
        at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:469)
        at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:28)
        at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:27)
        at com.yysoft.util.filter.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:111)
        at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:27)
        at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:6458)
        at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java(Compiled Code))
        at weblogic.security.service.SecurityManager.runAs(SecurityManager.java(Compiled Code))
        at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletContext.java:3661)
        at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java:2630)
        at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java(Compiled Code))
        at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:178)

Answer 1

TimeSeriesCollection dataset = new TimeSeriesCollection();
      dataset.addSeries(s1);JFreeChart chart = ChartFactory.createTimeSeriesChart(
           "",
           "","",
           dataset,
           true,
           true,
           false
       );FileOutputStream fos_jpg = null;
try {
         fos_jpg = new FileOutputStream(application.getRealPath("/")+"main/weatherInsepct/autoStation/w"+StationID+".jpg");
ChartUtilities.writeChartAsJPEG(fos_jpg,100,chart,600,300,null);
}
catch(Exception e)
{}finally {
try {
fos_jpg.close();
} catch (Exception e) {}
}代码。。大家快帮帮忙