[#3831] - Error in preview

I'm not the case opener but I'm getting the same exact error on the attached report.

When it happens: As soon as I try to switch to Preview tab of the report(which doesn't have that much, don't think it's jrxml problem).
JSS version: 6.0.0.final
IDE: Eclipse Kepler SR2 (4.3.2) with STS 3.6.3.201411281414-RELEASE-e43
OS: Windows 7 Enterprise SP1
Java: 1.7

Let me know if you need more info
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UPDATE: The error does mean something after digging through my classpath, slf4j-log4j12.jar is the culprit for this issue causing the failure to preview error.
This sounds more of a bug so I'm changing the ticket status accordingly.

For this issue, will you release a new version of the plugin? Yesterday, I updated Jaspersoft Studio from 6.0.0 to 6.0.1. I was able to build the jrxml, but I experienced the error when I attempted to compile.

Thanks,
Mike

still happens in Eclipse (Kepler) Preview with 6.1.0, but not with another Eclipse running with 5.5.1.final ... for us it's the usage of org.slf4j.Logger (having slf4j-api-1.7.5.jar and slf4j-simple-1.7.5.jar in the build path or having both removed - does not matter. where these are called by a custom scriptlet)

running Eclipse with the eclipse.ini jvm option "-Dverbose:class" shows that the conflict may be related to this other loaded class (wherever it is loaded (maybe used by jasper preview editor itself): eclipse/plugins/org.slf4j.api_1.7.2.v20121108-1250.jar)

I suppose Jasper uses SLF4J since v6 and does not isolate its class loading of report-specific classes/libs with a separate class loader from its own class versions (or the ones provided by the Eclipse installation) and thus such linkage errors (e.g. http://stackoverflow.com/questions/244482/how-to-deal-with-linkageerrors...) may be caused.

Exception details:
net.sf.jasperreports.engine.JRException: net.sf.jasperreports.engine.fill.JRExpressionEvalException: Error evaluating expression for source text: $P{REPORT_SCRIPTLET}.setTestRaw_LogOn_TstMsgOn(true, true)
Caused by: net.sf.jasperreports.engine.fill.JRExpressionEvalException: Error evaluating expression for source text: $P{REPORT_SCRIPTLET}.setTestRaw_LogOn_TstMsgOn(true, true)
Caused by: java.lang.LinkageError: loader constraint violation: loader (instance of java/net/FactoryURLClassLoader) previously initiated loading for a different type with name "org/slf4j/Logger"

Posted this also here: http://stackoverflow.com/a/31719746/1915920

Same for me, the issue is still present on Jasper Studio 6.3.1. I'm using a BeanDataAdapter for testing reports. Whenever I make a change to the DataAdapter and try to view the report preview I'm getting the error mentioned below. The problem can only be solved by restarting Eclipse (which is a total pain if you have large workspace with 300+ modules). Thus, JasperReports is currently unusable for me.

net.sf.jasperreports.engine.JRException: net.sf.jasperreports.engine.fill.JRExpressionEvalException: Error evaluating expression for source text: $F{header}.getPostalAddress()
at com.jaspersoft.studio.editor.preview.view.control.ReportControler.fillReport(ReportControler.java:548)

Caused by: java.lang.LinkageError: loader constraint violation: loader (instance of net/sf/jasperreports/engine/util/JRClassLoader) previously initiated loading for a different type with name "foo.bar.MyClass"
at MaterialReport_1481274379408_337847.evaluate(MaterialReport_1481274379408_337847:257)
at net.sf.jasperreports.engine.fill.JREvaluator.evaluate(JREvaluator.java:276)
... 14 more

Hi CrazyT, thanks for providing a possible solution and test case.
We will try to look into it for the next releases.

Regards,
Massimo.