value not appearing in data table jsf - jsf

Question

I'm trying to get value from 7 classes, for 7 columns
for interval one, interval two and so on for each student I have >
but the data table get's empty, but Java code is working fine.
I think the problem in html code tags
here is:
</h:form>
<h:form id="hesham1">
<p:scrollPanel style="width:100%;height:100%">
<p:dataTable var="car" value="#{tableBean.carsSmall}" id="hesham" encoding="windows-1256" dir="rtl" emptyMessage="لا يوجد بيانات او تأكد من البيانات المستعلم عنها">
<f:facet name="header">
الاستعلام عن صف 2-10
</f:facet>
<p:columnGroup type="header">
<p:row>
<p:column rowspan="2" headerText="اسم الطالب"/>
<p:column rowspan="2" headerText="التاريخ" />
<p:column colspan="3" headerText="الحصة الاولى" style="text-align: center;"/>
<p:column colspan="3" headerText="الحصة الثانية" style="text-align: center;"/>
<p:column colspan="3" headerText="الحصة الثالثة" style="text-align: center;"/>
<p:column colspan="3" headerText="الحصة الرابعة" style="text-align: center;"/>
<p:column colspan="3" headerText="الحصة الخامسة" style="text-align: center;"/>
<p:column colspan="3" headerText="الحصة السادسة" style="text-align: center;"/>
<p:column colspan="3" headerText="الحصة السابعة" style="text-align: center;"/>
</p:row>
<p:row>
<p:column headerText="المعلم" >
<h:outputText value="#{car.teachers}" />
</p:column>
<p:column headerText="الماده" >
</p:column>
<p:column headerText="الحالة" >
<h:outputText value="#{car.state}" />
</p:column>
<p:column headerText="المعلم" >
<h:outputText value="#{interval2.teachers2}" />
</p:column>
<p:column headerText="الماده" />
<p:column headerText="الحالة" >
<h:outputText value="#{interval2.state2}" />
</p:column>
<p:column headerText="المعلم" >
<h:outputText value="#{interval3.teachers3}" />
</p:column>
<p:column headerText="الماده" />
<p:column headerText="الحالة" >
<h:outputText value="#{interval3.state3}" />
</p:column>
<p:column headerText="المعلم" >
<h:outputText value="#{interval4.teachers4}" />
</p:column>
<p:column headerText="الماده" />
<p:column headerText="الحالة" >
<h:outputText value="#{interval4.state4}" />
</p:column>
<p:column headerText="المعلم" >
<h:outputText value="#{interval5.teachers5}" />
</p:column>
<p:column headerText="الماده" />
<p:column headerText="الحالة" >
<h:outputText value="#{interval5.state5}" />
</p:column>
<p:column headerText="المعلم" >
<h:outputText value="#{interval6.teachers6}" />
</p:column>
<p:column headerText="الماده" />
<p:column headerText="الحالة" >
<h:outputText value="#{interval6.state6}" />
</p:column>
<p:column headerText="المعلم" >
<h:outputText value="#{interval7.teachers7}" />
</p:column>
<p:column headerText="الماده" />
<p:column headerText="الحالة" >
<h:outputText value="#{interval7.state7}" />
</p:column>
</p:row>
</p:columnGroup>
<f:facet name="footer">
اجمالي عدد الاستعلامات #{fn:length(tableBean.carsSmall)}
</f:facet>
</p:dataTable>
</p:scrollPanel>
<br />
<h:commandButton value="طباعة التقرير" type="button"
icon="ui-icon-print">
<p:printer target="hesham" />
</h:commandButton>
</h:form>

Answer 1

Um.. you simply don't have a table body here. Everything you have is an enormous header, incorrectly referencing the iteration variable and a giant footer.
See this example for how it's done properly, the p:columnGroup only enclosing the header:
<p:dataTable id="salesTable" var="sale" value="#{tableBean.sales}">
<f:facet name="header">
Sales/Profits of Manufacturers
</f:facet>
<p:columnGroup type="header">
<p:row>
<p:column rowspan="2" headerText="Manufacturer" />
<p:column colspan="2" headerText="Sales" />
</p:row>
<p:row>
<p:column headerText="Sales Count" />
<p:column headerText="Profit" />
</p:row>
</p:columnGroup>
<p:column>
#{sale.manufacturer}
</p:column>
<p:column>
#{sale.lastYearProfit}%
</p:column>
</p:dataTable>