极品问题什么原因引起的？求解……

org.apache.jasper.JasperException: An exception occurred processing JSP page /vote_result.jsp at line 114111:  i ++;
112:  }
113:    
114:  filename = charUtil.createBarImage(rowKeys, columnKeys, data, str_vote[5],session, 300, 180);
115:  graphURL = request.getContextPath() + "/servlet/DisplayChart?filename=" + filename;
116:  } else {
117:  out.println("<tr>");
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
root cause java.lang.IllegalArgumentException: Duplicate items in 'rowKeys'.
org.jfree.data.general.DatasetUtilities.createCategoryDataset(DatasetUtilities.java:426)
net.sz600.jfreechart.JFChartUtil.createBarImage(JFChartUtil.java:110)
org.apache.jsp.vote_005fresult_jsp._jspService(vote_005fresult_jsp.java:192)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)