#168 NullPointerException during xls export in 2.0_SNAPSHOT

[GeniousMonkey]

actually it's a bug in the 2.0-SNAPSHOT so I understand but maybe it will help.

During xls export we got a NullPointerException:
java.lang.NullPointerException
at org.displaytag.export.excel.ExcelHssfView.doExport(ExcelHssfView.java:139)
at com.bureauveritas.pcmportal.web.taglib.displaytag.AjaxTableTag.writeExport(AjaxTableTag.java:1284)
at com.bureauveritas.pcmportal.web.taglib.displaytag.AjaxTableTag.doExport(AjaxTableTag.java:1240)
at com.bureauveritas.pcmportal.web.taglib.displaytag.AjaxTableTag.doEndTag(AjaxTableTag.java:1119)
at org.apache.jsp.pages.gsit.shipment.list_jsp._jspService(list_jsp.java:762)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)

Apparently this field is never initialized:
HSSFWorkbook org.displaytag.export.excel.ExcelHssfView.wb