Jaspersoft Studio complains class cast exception when using JRBeanCollectionDataSource

Question

I have a weird problem with Jaspersoft Studio and custom JRBeanCollectionDataSource.

Every time I try to access child object of parent object, I get exception like this:

net.sf.jasperreports.engine.JRException: net.sf.jasperreports.engine.fill.JRExpressionEvalException: Error evaluating expression : 
    Source text : $F{test}.getFirst() + " " + $F{test}.getSecond()
    at com.jaspersoft.studio.editor.preview.view.control.ReportControler.fillReport(ReportControler.java:466)
    at com.jaspersoft.studio.editor.preview.view.control.ReportControler.access$18(ReportControler.java:441)
    at com.jaspersoft.studio.editor.preview.view.control.ReportControler$4.run(ReportControler.java:333)
    at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)
Caused by: net.sf.jasperreports.engine.fill.JRExpressionEvalException: Error evaluating expression : 
    Source text : $F{test}.getFirst() + " " + $F{test}.getSecond()
    at net.sf.jasperreports.engine.fill.JREvaluator.evaluate(JREvaluator.java:263)
    at net.sf.jasperreports.engine.fill.JRCalculator.evaluate(JRCalculator.java:611)
    at net.sf.jasperreports.engine.fill.JRCalculator.evaluate(JRCalculator.java:579)
    at net.sf.jasperreports.engine.fill.JRFillElement.evaluateExpression(JRFillElement.java:1016)
    at net.sf.jasperreports.engine.fill.JRFillTextField.evaluateText(JRFillTextField.java:504)
    at net.sf.jasperreports.engine.fill.JRFillTextField.evaluate(JRFillTextField.java:488)
    at net.sf.jasperreports.engine.fill.JRFillElementContainer.evaluate(JRFillElementContainer.java:259)
    at net.sf.jasperreports.engine.fill.JRFillBand.evaluate(JRFillBand.java:456)
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillBandNoOverflow(JRVerticalFiller.java:467)
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillColumnHeader(JRVerticalFiller.java:512)
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReportStart(JRVerticalFiller.java:294)
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReport(JRVerticalFiller.java:152)
    at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:963)
    at net.sf.jasperreports.engine.fill.BaseFillHandle$ReportFiller.run(BaseFillHandle.java:120)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassCastException: mypacket.Test cannot be cast to mypacket.Test
    at Blank_A4_1403082997789_739077.evaluate(Blank_A4_1403082997789_739077:169)
    at net.sf.jasperreports.engine.fill.JREvaluator.evaluate(JREvaluator.java:250)
    ... 14 more

Here is relevant classes:

public class RootFactory {

    public static JRBeanCollectionDataSource get() {
        return new JRBeanCollectionDataSource(Arrays.asList(new RootClass(new Test())));
    }
}


public class RootClass {
    private Test test;

    public RootClass(Test test) {
        this.test = test;
    }

    public Test getTest() {
        return test;
    }

    public void setTest(Test test) {
        this.test = test;
    }
}


public class Test {

    private String first = "first";
    private String second = "second";

    public String getFirst() {
        return first;
    }

    public void setFirst(String first) {
        this.first = first;
    }

    public String getSecond() {
        return second;
    }

    public void setSecond(String second) {
        this.second = second;
    }
}

I've added classes to Jaspersoft Studio and added data adapter to use RootFactory.get() method and that seems to be working.

Field expression in jasper is $F{test}.getFirst() + " " + $F{test}.getSecond()

Weird thing is that jasper can't cast mypacket.Test to mypacket.Test.

Any clues how to solve this?

- Jaspersoft studio 5.6.0
- Java 1.7.0_11

Edit 1

Here is jrxml file

<?xml version="1.0" encoding="UTF-8"?>
<!-- Created with Jaspersoft Studio version last-->
<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="Blank_A4" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" uuid="a333429d-13c8-4db0-849e-9ed3fa97af6e">
<property name="com.jaspersoft.studio.data.defaultdataadapter" value="TempFactory"/>
<queryString>
    <![CDATA[]]>
</queryString>
<field name="test" class="mypacket.Test"/>
<background>
    <band splitType="Stretch"/>
</background>
<title>
    <band height="79" splitType="Stretch"/>
</title>
<pageHeader>
    <band height="35" splitType="Stretch"/>
</pageHeader>
<columnHeader>
    <band height="61" splitType="Stretch">
        <textField>
            <reportElement x="0" y="0" width="555" height="61" uuid="0ca07834-5483-4ad5-a7fc-b415c2cce367"/>
            <textFieldExpression><![CDATA[$F{test}.getFirst() + " " + $F{test}.getSecond()]]></textFieldExpression>
        </textField>
    </band>
</columnHeader>
<detail>
    <band height="125" splitType="Stretch"/>
</detail>
<columnFooter>
    <band height="45" splitType="Stretch"/>
</columnFooter>
<pageFooter>
    <band height="54" splitType="Stretch"/>
</pageFooter>
<summary>
    <band height="42" splitType="Stretch"/>
</summary>
</jasperReport>

And if it does matter: I use osx 10.9.2.

In Jasper report create a field named test.first and call it like this: $F{test.first} — user1791574, Jun 18 '14 at 11:16

score 4 · Answer 1 · answered Jul 08 '14 at 11:10

4

I have faced similar exceptions in both 5.5.2 and 5.6, like ...cannot cast from T to T... where T always was a) the exact same type b) an own pojo derived fr JRAbstractBeanDataSource

I know this is not really a solution and think this probably should be filed to the Jasper guys... but just plain "restarting jasper studio" always helped :-/ One of many little things in studio...

Hope it kinda helps nonetheless

answered Jul 08 '14 at 11:10

ton

41
1

2

Worked for me. Seems to be an annoying bug in Studio. – Dalton Sep 26 '14 at 14:04

score 0 · Answer 2 · answered May 22 '15 at 22:36

Restarting Jasper Studio did not work for me.

I think this is still a bug in Jasper Studio 6.0.4 standalone version. But when I install Studio software as an Eclipse plugin and preview the report from the Java project, it works fine without any problems.

The good thing is I can set the report to be backward compatible with Jasper Reports version 4.5.0 so it does not create the UUID elements all over the report every time I preview the report and the eclipse plugin also works with Java 8 SDK

tinesoft · Answer 3 · 2023-01-22T08:14:45.650

For anyone coming to this thread and and still having the issue, I managed to solve it in my case, by doing so:

Right-click on the project -> "Build Path" -> "Configure Build path..."
Navigate to "Order and Export" tab
Uncheck "Jaspersoft Server Library" ("JRE System Library" must be checked though)
Apply and close
Restart Jasperstudio
Go back to "Preview" and rerun the generation of the report
Enjoy!

In fact, the problem was that different classes loaders were used to load the same class T:

The default classloader from "JRE System Library"
The one from "Jaspersoft Server Library"

You can confirm this by looking the error stacktrace in full (notice the different instances of the classloader, in bold):

Caused by: java.lang.ClassCastException: class <full.package.to.class.T> cannot be cast to class <full.package.to.class.T>(<full.package.to.class.T> is in unnamed module of loader java.net.FactoryURLClassLoader @7fe379ab; <full.package.to.class.T> is in unnamed module of loader java.net.FactoryURLClassLoader @4b9b57d9)

Jaspersoft Studio complains class cast exception when using JRBeanCollectionDataSource

3 Answers3