I'm trying to display the contents of an array ("multi_values" in the JSON sample below) in a sub-report, but I'm missing something. The sub-report does display the correct number of Detail entries (i.e., 2 for item_name 'a' and 3 for item_name 'b'), so I know it's getting the array. However, despite numerous attempts, the subreport's textfield only ever displays "null". I have a couple of ideas where things could be going wrong, but I've been unable to find any documentation or questions relating to such an array in JSON data: * The multi_values field in the main report should have a different class (I've tried multiple other classes but nothing works) * The multi_value field in the sub-report needs a different field.expression value (again, I've tried multiple things and just left "multi_value" here as a placeholder) * The queryString in the sub-report needs to be something else Any input would be greatly appreciated. Here's the heavily reduced JSON: { "items": [ { "item_name": "a", "multi_values": ["value1", "value2"] }, { "item_name": "b", "multi_values": ["value3", "value4", "value5"] } ]} The main report: <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="MultiValueExample" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" uuid="988c6c04-ee0c-4e28-8121-de3584ad30b4"> <property name="com.jaspersoft.studio.data.defaultdataadapter" value="MultiValueExample.xml"/> <queryString language="jsonql"> <![CDATA[items]]> </queryString> <field name="item_name" class="java.lang.String"> <property name="net.sf.jasperreports.jsonql.field.expression" value="item_name"/> <fieldDescription><![CDATA[item_name]]></fieldDescription> </field> <field name="multi_values0" class="java.lang.String"> <property name="net.sf.jasperreports.jsonql.field.expression" value="multi_values[0]"/> <fieldDescription><![CDATA[multi_values0]]></fieldDescription> </field> <field name="multi_values" class="java.lang.String"> <property name="net.sf.jasperreports.jsonql.field.expression" value="multi_values"/> <fieldDescription><![CDATA[multi_values]]></fieldDescription> </field> <detail> <band height="59" splitType="Stretch"> <textField> <reportElement x="0" y="0" width="100" height="16" uuid="90cf147e-e35f-4a6a-8de2-87287688a229"> <property name="com.jaspersoft.studio.unit.height" value="px"/> </reportElement> <textFieldExpression><![CDATA[$F{item_name}]]></textFieldExpression> </textField> <textField> <reportElement x="110" y="0" width="100" height="16" uuid="90cf147e-e35f-4a6a-8de2-87287688a229"> <property name="com.jaspersoft.studio.unit.height" value="px"/> </reportElement> <textFieldExpression><![CDATA[$F{multi_values0}]]></textFieldExpression> </textField> <subreport> <reportElement x="0" y="18" width="480" height="40" uuid="cf743a67-8fcb-407d-9762-848428411202"/> <dataSourceExpression><![CDATA[((net.sf.jasperreports.engine.data.JsonQLDataSource)($P{REPORT_DATA_SOURCE})).subDataSource("multi_values")]]></dataSourceExpression> <subreportExpression><![CDATA["MultiValueExampleSub.jasper"]]></subreportExpression> </subreport> </band> </detail></jasperReport> And the sub-report: <jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="MultiValueExampleSub" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" uuid="6c426da9-4d08-46e0-a3fa-da99beedbeed"> <property name="com.jaspersoft.studio.data.defaultdataadapter" value="One Empty Record"/> <queryString language="jsonql"> <![CDATA[]]> </queryString> <field name="multi_value" class="java.lang.String"> <property name="net.sf.jasperreports.jsonql.field.expression" value="multi_value"/> <fieldDescription><![CDATA[multi_value]]></fieldDescription> </field> <detail> <band height="21"> <textField> <reportElement x="0" y="0" width="280" height="16" uuid="c6e03595-dba0-49ea-bc8f-224fd23a45c9"> <property name="com.jaspersoft.studio.unit.height" value="px"/> </reportElement> <box> <topPen lineWidth="1.0" lineStyle="Solid" lineColor="#000000"/> <leftPen lineWidth="1.0" lineStyle="Solid" lineColor="#000000"/> <bottomPen lineWidth="1.0" lineStyle="Solid" lineColor="#000000"/> <rightPen lineWidth="1.0" lineStyle="Solid" lineColor="#000000"/> </box> <textFieldExpression><![CDATA[$F{multi_value}]]></textFieldExpression> </textField> </band> </detail></jasperReport>