JasperReports: Subreport renders multiple times, causing duplicate pages

Question

I am using JasperReports to generate a graph and table for a web application using two separate queries. My main JRXML generates the graph, and I include a subreport in the Detail band to generate the table. However, when it renders, the subreport seems to get rendered multiple times (12 to be exact), which results in the generated report being the same graph and table on 12 pages (exact duplicates of each other). This happens both through the online application and iReport.

My main JRXML, subreport JRXML, and report generation code are below (some details have been removed for NDA reasons).

Any insight or ideas on what the issue is would be very helpful.

Main JRXML:

    <?xml version="1.0" encoding="UTF-8"?>
    <jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="report" language="groovy" pageWidth="842" pageHeight="595" orientation="Landscape" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20">
        <property name="ireport.zoom" value="1.0"/>
        <property name="ireport.x" value="0"/>
        <property name="ireport.y" value="0"/>
        <parameter name="SUBREPORT_DIR" class="java.lang.String" isForPrompting="false">
            <defaultValueExpression><![CDATA["<<PATH_TO_SUBREPORT>>"]]></defaultValueExpression>
        </parameter>
        <parameter name="param" class="java.util.Collection" />     
     <queryString language="SQL">
            <![CDATA[<<DATABASE_QUERY>>]]>
        </queryString>
        <field name="FIELD1" class="java.lang.Integer"/>
        <field name="FIELD2" class="java.sql.Date"/>
        <field name="FIELD3" class="java.math.BigDecimal"/>
        <field name="FIELD4" class="java.math.BigDecimal"/>
        <field name="FIELD5" class="java.math.BigDecimal"/>
        <background>
            <band splitType="Stretch"/>
        </background>
        <title>
            <band height="10" splitType="Stretch"/>
        </title>
        <pageHeader>
            <band height="5" splitType="Stretch"/>
        </pageHeader>
        <columnHeader>
            <band height="5" splitType="Stretch"/>
        </columnHeader>
        <detail>
            <band height="513" splitType="Stretch">
                <lineChart>
                    <chart>
                        <reportElement positionType="Float" x="51" y="0" width="680" height="400"/>
                        <chartTitle/>
                        <chartSubtitle/>
                        <chartLegend/>
                    </chart>
                    <categoryDataset>
                        <categorySeries>
                            <seriesExpression><![CDATA["FIELD1"]]></seriesExpression>
                            <categoryExpression><![CDATA[$F{f1}]]></categoryExpression>
                            <valueExpression><![CDATA[$F{f2}]]></valueExpression>
                        </categorySeries>
                        <categorySeries>
                            <seriesExpression><![CDATA["FIELD2"]]></seriesExpression>
                            <categoryExpression><![CDATA[$F{f1}]]></categoryExpression>
                            <valueExpression><![CDATA[$F{f2}]]></valueExpression>
                        </categorySeries>
                        <categorySeries>
                            <seriesExpression><![CDATA["FIELD3"]]></seriesExpression>
                            <categoryExpression><![CDATA[$F{f1}]]></categoryExpression>
                            <valueExpression><![CDATA[$F{f2}]]></valueExpression>
                        </categorySeries>
                    </categoryDataset>
                    <linePlot>
                        <plot labelRotation="-90.0"/>
                        <categoryAxisFormat labelRotation="-90.0">
                            <axisFormat>
                                <tickLabelFont>
                                    <font size="12"/>
                                </tickLabelFont>
                            </axisFormat>
                        </categoryAxisFormat>
                        <rangeAxisMinValueExpression><![CDATA[0]]></rangeAxisMinValueExpression>
                        <rangeAxisMaxValueExpression><![CDATA[101]]></rangeAxisMaxValueExpression>
                    </linePlot>
                </lineChart>
                <subreport>
                    <reportElement x="377" y="413" width="425" height="100"/>
                    <subreportParameter name="param">
                        <subreportParameterExpression><![CDATA[$P{param}]]></subreportParameterExpression>
                    </subreportParameter>
                    <connectionExpression><![CDATA[$P{REPORT_CONNECTION}]]></connectionExpression>
                    <subreportExpression><![CDATA[$P{SUBREPORT_DIR} + "testReport.jasper"]]></subreportExpression>
                </subreport>
            </band>
        </detail>
        <columnFooter>
            <band height="5" splitType="Stretch"/>
        </columnFooter>
        <pageFooter>
            <band height="15" splitType="Stretch">
                <textField>
                    <reportElement mode="Opaque" x="3" y="2" width="759" height="13" backcolor="#E6E6E6"/>
                    <textElement textAlignment="Right"/>
                    <textFieldExpression><![CDATA["Page "+$V{PAGE_NUMBER}+" of"]]></textFieldExpression>
                </textField>
                <textField evaluationTime="Report">
                    <reportElement mode="Opaque" x="762" y="2" width="40" height="13" backcolor="#E6E6E6"/>
                    <textElement/>
                    <textFieldExpression><![CDATA[" " + $V{PAGE_NUMBER}]]></textFieldExpression>
                </textField>
                <textField pattern="EEEEE dd MMMMM yyyy">
                    <reportElement x="3" y="0" width="100" height="13"/>
                    <textElement/>
                    <textFieldExpression><![CDATA[new SimpleDateFormat("MM-dd-yyyy").format(
    new java.util.Date())]]></textFieldExpression>
                </textField>
            </band>
        </pageFooter>
        <summary>
            <band height="10" splitType="Stretch"/>
        </summary>
    </jasperReport>

Sub Report JRXML:

<?xml version="1.0" encoding="UTF-8"?>
<jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="evcas_sub" language="groovy" pageWidth="450" pageHeight="150" columnWidth="10" leftMargin="10" rightMargin="10" topMargin="10" bottomMargin="10">
    <property name="ireport.zoom" value="1.0"/>
    <property name="ireport.x" value="0"/>
    <property name="ireport.y" value="0"/>
    <style name="table">
        <box>
            <pen lineWidth="1.0" lineColor="#000000"/>
        </box>
    </style>
    <style name="table_TH" mode="Opaque" backcolor="#0000FF">
        <box>
            <pen lineWidth="0.5" lineColor="#000000"/>
        </box>
    </style>
    <style name="table_CH" mode="Opaque" backcolor="#BFBFFF">
        <box>
            <pen lineWidth="0.5" lineColor="#000000"/>
        </box>
    </style>
    <style name="table_TD" mode="Opaque" backcolor="#FFFFFF">
        <box>
            <pen lineWidth="0.5" lineColor="#000000"/>
        </box>
        <conditionalStyle>
            <conditionExpression><![CDATA[new Boolean($V{REPORT_COUNT}.intValue()%2==0)]]></conditionExpression>
            <style backcolor="#EFEFFF"/>
        </conditionalStyle>
    </style>
    <style name="Crosstab Data Text" hAlign="Center"/>
    <parameter name="param" class="java.util.Collection" />
    <queryString>
        <![CDATA[<<DATABASE_QUERY>>]]>
    </queryString>
    <field name="FIELD1" class="java.lang.String"/>
    <field name="FIELD2" class="java.math.BigDecimal"/>
    <field name="FIELD3" class="java.math.BigDecimal"/>
    <field name="FIELD4" class="java.math.BigDecimal"/>
    <field name="FIELD5" class="java.math.BigDecimal"/>
    <field name="FIELD6" class="java.math.BigDecimal"/>
    <field name="FIELD7" class="java.math.BigDecimal"/>
    <field name="FIELD8" class="java.math.BigDecimal"/>
    <background>
        <band splitType="Stretch"/>
    </background>
    <title>
        <band height="5" splitType="Stretch"/>
    </title>
    <pageHeader>
        <band height="5"/>
    </pageHeader>
    <columnHeader>
        <band height="12">
            <textField>
                <reportElement style="table_TH" x="0" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="9"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA["FIELD1"]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_TH" x="50" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="9"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA["FIELD2"]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_TH" x="100" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="9"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA["FIELD3"]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_TH" x="150" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="9"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA["FIELD4"]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_TH" x="200" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="9"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA["FIELD5"]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_TH" x="250" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="9"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA["FIELD6"]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_TH" x="300" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="9"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA["FIELD7"]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_TH" x="350" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="9"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA["FIELD8"]]></textFieldExpression>
            </textField>
        </band>
    </columnHeader>
    <detail>
        <band height="12">
            <textField>
                <reportElement style="table_CH" x="0" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="8"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA[$F{f1}]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_CH" x="50" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="8"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA[$F{f2}]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_CH" x="100" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="8"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA[$F{f3}]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_CH" x="150" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="8"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA[$F{f4}]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_CH" x="200" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="8"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA[$F{f5}]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_CH" x="250" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="8"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA[$F{f6}]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_CH" x="300" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="8"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA[$F{f7}]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement style="table_CH" x="350" y="0" width="50" height="12" backcolor="#FFFFFF"/>
                <textElement>
                    <font size="8"/>
                    <paragraph leftIndent="2"/>
                </textElement>
                <textFieldExpression><![CDATA[$F{f8}]]></textFieldExpression>
            </textField>
        </band>
    </detail>
    <columnFooter>
        <band height="5" splitType="Stretch"/>
    </columnFooter>
    <pageFooter>
        <band height="5" splitType="Stretch"/>
    </pageFooter>
</jasperReport>

Rendering Code:

String strFileName = "<<FILENAME>>";
File jrxml = new File(strFileName);
InputStream iStream = new FileInputStream(jrxml);
JasperReport objJReport = JasperCompileManager.compileReport(iStream);
JasperPrint objJPrint = JasperFillManager.fillReport(objJReport, hashMap, datasource.getConnection());
JasperExportManager.exportReportToPdfStream(objJPrint, os);

Answer 1

One detail band is printed per record in your data set. So if your database query returns 12 rows, you get 12 copies of the detail band. Each band uses data from a single row, but this is inconsequential for you as you are using a chart and subreport to display the data.

To avoid this repetition, just put your chart and subreport into a different band. I'd go for column header or footer, but anything except detail will work.