public   class  MyTable {

     private   int [][] data =  null ;
    
     public  String changeData() {
         if  (zzzzz) {
            data =  new   int [][] {{ 1 , 1 }, { 1 , 1 }, { 1 , 1 }, { 1 , 1 }};
        }  else  {
            data =  new   int [][] {{ 2 , 2 , 2 }, { 2 , 2 , 2 }};
        }
    }

    ....
}    

           <h:dataTable var="record" value="#{RoutingTableBean.records}">
            <c:forEach var="item" begin="1" end="${RoutingTableBean.columnCount}">
               <h:column id="z1">
                  <f:facet name="header">
                     <h:outputText id="z2" value="#{RoutingTableBean.header}"/>
                  </f:facet>
                  <h:outputText id="z3" value="#{record.value}"/>
               </h:column>
            </c:forEach>
          </h:dataTable>