title: Why am I getting "Document is empty" when I preview in Jasper studio book mode?
body: <p>I use Jasper Report studio to design the report using the book template, I'm sure a single report is ok, but when I preview the merged report, I found that an empty document is returned, showing &quot;Document is empty&quot;, the following is the code of the main page. Please help me!</p>
  <pre class="lang-xml prettyprint-override"><code>&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
  &lt;!-- Created with Jaspersoft Studio version 6.19.1.final using JasperReports Library version 6.19.1-867c00bf88cd4d784d404379d6c05e1b419e8a4c  --&gt;
  &lt;jasperReport xmlns=&quot;http://jasperreports.sourceforge.net/jasperreports&quot; xmlns:xsi=&quot;http://www.w3.org/2001/XMLSchema-instance&quot; xsi:schemaLocation=&quot;http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd&quot; name=&quot;healthdoc&quot; pageWidth=&quot;595&quot; pageHeight=&quot;842&quot; whenNoDataType=&quot;AllSectionsNoDetail&quot; sectionType=&quot;Part&quot; columnWidth=&quot;555&quot; leftMargin=&quot;20&quot; rightMargin=&quot;20&quot; topMargin=&quot;30&quot; bottomMargin=&quot;30&quot; whenResourceMissingType=&quot;Empty&quot; uuid=&quot;d2716064-8ae4-40cf-a575-33afba400e3a&quot;&gt;
      &lt;property name=&quot;com.jaspersoft.studio.data.defaultdataadapter&quot; value=&quot;business&quot;/&gt;
      &lt;property name=&quot;net.sf.jasperreports.print.create.bookmarks&quot; value=&quot;true&quot;/&gt;
      &lt;property name=&quot;com.jaspersoft.studio.data.sql.tables&quot; value=&quot;&quot;/&gt;
      &lt;property name=&quot;com.jaspersoft.studio.book.group.cover.header&quot; value=&quot;Cover and Contents&quot;/&gt;
      &lt;property name=&quot;com.jaspersoft.studio.book.group.cover.footer&quot; value=&quot;Backcover&quot;/&gt;
      &lt;property name=&quot;ireport.jasperserver.url&quot; value=&quot;http://10.0.1.33:8188/jasperserver/&quot;/&gt;
      &lt;property name=&quot;ireport.jasperserver.user&quot; value=&quot;jasperadmin&quot;/&gt;
      &lt;property name=&quot;ireport.jasperserver.report.resource&quot; value=&quot;/reports/hms/hms_doc_files/main_jrxml&quot;/&gt;
      &lt;property name=&quot;ireport.jasperserver.reportUnit&quot; value=&quot;/reports/hms/hms_doc&quot;/&gt;
      &lt;style name=&quot;Title&quot; forecolor=&quot;#FFFFFF&quot; fontName=&quot;stsong&quot; fontSize=&quot;50&quot; isBold=&quot;false&quot; pdfFontName=&quot;stsong&quot;/&gt;
      &lt;style name=&quot;SubTitle&quot; forecolor=&quot;#CCCCCC&quot; fontName=&quot;stsong&quot; fontSize=&quot;18&quot; isBold=&quot;false&quot; pdfFontName=&quot;stsong&quot;/&gt;
      &lt;style name=&quot;Column header&quot; forecolor=&quot;#666666&quot; fontName=&quot;stsong&quot; fontSize=&quot;14&quot; isBold=&quot;true&quot; pdfFontName=&quot;stsong&quot;/&gt;
      &lt;style name=&quot;Detail&quot; mode=&quot;Transparent&quot; fontName=&quot;stsong&quot; pdfFontName=&quot;stsong&quot;/&gt;
      &lt;parameter name=&quot;id&quot; class=&quot;java.lang.Integer&quot;&gt;
          &lt;defaultValueExpression&gt;&lt;![CDATA[1317]]&gt;&lt;/defaultValueExpression&gt;
      &lt;/parameter&gt;
      &lt;queryString language=&quot;SQL&quot;&gt;
          &lt;![CDATA[select 1 FROM  mem_guest t]]&gt;
      &lt;/queryString&gt;
      &lt;group name=&quot;cover&quot;&gt;
          &lt;groupHeader&gt;
              &lt;part uuid=&quot;48cb43f5-1d78-4a4e-94c7-bc80581e2049&quot;&gt;
                  &lt;property name=&quot;net.sf.jasperreports.bookmarks.data.source.parameter&quot; value=&quot;REPORT_DATA_SOURCE&quot;/&gt;
                  &lt;p:subreportPart xmlns:p=&quot;http://jasperreports.sourceforge.net/jasperreports/parts&quot; xsi:schemaLocation=&quot;http://jasperreports.sourceforge.net/jasperreports/parts http://jasperreports.sourceforge.net/xsd/parts.xsd&quot;&gt;
                      &lt;subreportParameter name=&quot;guestId&quot;&gt;
                          &lt;subreportParameterExpression&gt;&lt;![CDATA[$P{id}]]&gt;&lt;/subreportParameterExpression&gt;
                      &lt;/subreportParameter&gt;
                      &lt;subreportExpression&gt;&lt;![CDATA[&quot;cover.jasper&quot;]]&gt;&lt;/subreportExpression&gt;
                  &lt;/p:subreportPart&gt;
              &lt;/part&gt;
              &lt;part evaluationTime=&quot;Report&quot; uuid=&quot;bf47c82d-6bc2-422e-97e2-dfa09e013bdb&quot;&gt;
                  &lt;property name=&quot;net.sf.jasperreports.bookmarks.data.source.parameter&quot; value=&quot;REPORT_DATA_SOURCE&quot;/&gt;
                  &lt;p:subreportPart xmlns:p=&quot;http://jasperreports.sourceforge.net/jasperreports/parts&quot; xsi:schemaLocation=&quot;http://jasperreports.sourceforge.net/jasperreports/parts http://jasperreports.sourceforge.net/xsd/parts.xsd&quot;&gt;
                      &lt;subreportParameter name=&quot;guestId&quot;&gt;
                          &lt;subreportParameterExpression&gt;&lt;![CDATA[$P{id}]]&gt;&lt;/subreportParameterExpression&gt;
                      &lt;/subreportParameter&gt;
                      &lt;subreportExpression&gt;&lt;![CDATA[&quot;content.jasper&quot;]]&gt;&lt;/subreportExpression&gt;
                  &lt;/p:subreportPart&gt;
              &lt;/part&gt;
          &lt;/groupHeader&gt;
      &lt;/group&gt;
  &lt;/jasperReport&gt;
  
  </code></pre>