Hello! I am running and developing against JaspersoftStudio-6.3.0.final. I use the Windows (64 Bit) and the Linux (64 Bit) versions. In both cases JDK 8u102 In the course of extending Jaspersoft Studio with own datasource implementations by an Eclipse plugin, I would like to use my own classes as parameter types. In this special case, it is an enum: net.august.clemens.TimeLevelEnum. Here, I come across 2 problems. First, in the parameter property window, net.august.clemens.TimeLevelEnum is not available when opening the class browser (clicking the '...' next to the class name input). I have to input "net.august.clemens.TimeLevelEnum" by hand. Nevertheless, when running the report, I get a nice combo box with the enum members as a parameter prompt, thus the class can be used. My question – is there maybe an extension point to "register" custom classes for the parameter properties dialogue? Second, I get an error when filling the report with a parameter of type net.august.clemens.TimeLevelEnum as input for a text field. But – I get this error only, when running the Linux version, under Windows the report fills just fine with the selected member of net.august.clemens.TimeLevelEnum. Is this due to a bug in the software, or is there a likely pointer to something I am not doing properly? It would be very nice to be able to use fully integrated custom types as parameters. Greetings, Clemens Here is the stack trace: net.sf.jasperreports.engine.JRException: net.sf.jasperreports.engine.fill.JRExpressionEvalException: Error evaluating expression for source text: $P{Timelevel} at com.jaspersoft.studio.editor.preview.view.control.ReportControler.fillReport(ReportControler.java:537) at com.jaspersoft.studio.editor.preview.view.control.ReportControler.access$20(ReportControler.java:512) at com.jaspersoft.studio.editor.preview.view.control.ReportControler$5.run(ReportControler.java:393) at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55) Caused by: net.sf.jasperreports.engine.fill.JRExpressionEvalException: Error evaluating expression for source text: $P{Timelevel} at net.sf.jasperreports.engine.fill.JREvaluator.evaluate(JREvaluator.java:290) at net.sf.jasperreports.engine.fill.JRCalculator.evaluate(JRCalculator.java:616) at net.sf.jasperreports.engine.fill.JRCalculator.evaluate(JRCalculator.java:584) at net.sf.jasperreports.engine.fill.JRFillElement.evaluateExpression(JRFillElement.java:1164) at net.sf.jasperreports.engine.fill.JRFillTextField.evaluateText(JRFillTextField.java:526) at net.sf.jasperreports.engine.fill.JRFillTextField.evaluate(JRFillTextField.java:510) at net.sf.jasperreports.engine.fill.JRFillElementContainer.evaluate(JRFillElementContainer.java:381) at net.sf.jasperreports.engine.fill.JRFillBand.evaluate(JRFillBand.java:500) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillTitle(JRVerticalFiller.java:311) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReportStart(JRVerticalFiller.java:247) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReport(JRVerticalFiller.java:115) at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:580) at net.sf.jasperreports.engine.fill.BaseFillHandle$ReportFill.run(BaseFillHandle.java:123) at java.lang.Thread.run(Thread.java:745) Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to net.august.clemens.TimeLevelEnum at Blank_A4_1474279094917_9823.evaluate(Blank_A4_1474279094917_9823:175) at net.sf.jasperreports.engine.fill.JREvaluator.evaluate(JREvaluator.java:276) ... 13 more