ClassCast exception when running report containing scriptlet

net.sf.jasperreports.engine.JRException:
net.sf.jasperreports.engine.JRException: Error creating scriptlet class instance : com.escout.app.reportWriter.InvoiceDetailsScriptlet
 at com.jaspersoft.studio.editor.preview.view.control.ReportControler.fillReport(ReportControler.java:468)
 at com.jaspersoft.studio.editor.preview.view.control.ReportControler.access$18(ReportControler.java:443)
 at com.jaspersoft.studio.editor.preview.view.control.ReportControler$4.run(ReportControler.java:335)
 at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54) 
Caused by: net.sf.jasperreports.engine.JRException: Error creating scriptlet class instance : com.escout.app.reportWriter.InvoiceDetailsScriptlet
 at net.sf.jasperreports.engine.scriptlets.DefaultScriptletFactory.getScriptlet(DefaultScriptletFactory.java:118)
 at net.sf.jasperreports.engine.scriptlets.DefaultScriptletFactory.getScriplets(DefaultScriptletFactory.java:69)
 at net.sf.jasperreports.engine.fill.JRFillDataset.createScriptlets(JRFillDataset.java:507)
 at net.sf.jasperreports.engine.fill.JRFillDataset.setParameterValues(JRFillDataset.java:626)
 at net.sf.jasperreports.engine.fill.JRBaseFiller.setParameters(JRBaseFiller.java:1313)
 at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:931)
 at net.sf.jasperreports.engine.fill.BaseFillHandle$ReportFiller.run(BaseFillHandle.java:120)
 at java.lang.Thread.run(Thread.java:745) 
Caused by: java.lang.ClassCastException: com.escout.app.reportWriter.InvoiceDetailsScriptlet cannot be cast to net.sf.jasperreports.engine.JRAbstractScriptlet
 at net.sf.jasperreports.engine.scriptlets.DefaultScriptletFactory.getScriptlet(DefaultScriptletFactory.java:110) 
... 7 more

Resolution:

This exception can indicate a problem with how the java class is implemented or used. Methods from that class are called in the report and are based on what they are inherting. Reviewing the code, the methods were not inheriting from the right class. To fix this, the following line was added to the problematic java class:

import net.sf.jasperreports.engine.*

Ref. Case #00056437