null pointer exception on Jasper studio with barcode (eclipse plugin)

[ddaitarn304gmail.com]

When putting two or more barcode in a report, you'll get random null pointer exception.

It's random, but easy to reproduce: simply put a "codabar" barcode with barcode4j, then add another "codabar" and switch from an item to another

here a stak trace from eclipse:

eclipse.buildId=4.5.2.M20151021-1000java.version=1.8.0_31java.vendor=Oracle CorporationBootLoader constants: OS=win32, ARCH=x86_64, WS=win32, NL=it_ITFramework arguments:  -product org.eclipse.epp.package.dsl.productCommand-line arguments:  -os win32 -ws win32 -arch x86_64 -product org.eclipse.epp.package.dsl.productcom.jaspersoft.studio.propertiesErrorMon Nov 02 12:01:48 CET 2015Problems occurred when invoking code from plug-in: "com.jaspersoft.studio.properties".java.lang.NullPointerException    at com.jaspersoft.studio.components.barcode.model.barcode4j.MBarcode4j.getPropertyValue(MBarcode4j.java:227)    at com.jaspersoft.studio.components.barcode.model.barcode4j.MEAN13.getPropertyValue(MEAN13.java:107)    at org.eclipse.ui.views.properties.PropertySheetEntry.refreshValues(PropertySheetEntry.java:590)    at org.eclipse.ui.views.properties.PropertySheetEntry.createChildEntries(PropertySheetEntry.java:253)    at org.eclipse.ui.views.properties.PropertySheetEntry.getChildEntries(PropertySheetEntry.java:340)    at org.eclipse.ui.views.properties.PropertySheetViewer.updateCategories(PropertySheetViewer.java:1096)    at org.eclipse.ui.views.properties.PropertySheetViewer.updateChildrenOf(PropertySheetViewer.java:1267)    at org.eclipse.ui.views.properties.PropertySheetViewer.setInput(PropertySheetViewer.java:988)    at org.eclipse.ui.views.properties.PropertySheetPage.refresh(PropertySheetPage.java:501)    at com.jaspersoft.studio.property.section.JDAdvancedSection$1.run(JDAdvancedSection.java:212)    at org.eclipse.swt.widgets.Synchronizer.syncExec(Synchronizer.java:186)    at org.eclipse.ui.internal.UISynchronizer.syncExec(UISynchronizer.java:145)... [/code]