java.lang.AssertionError
   at net.sourceforge.plantuml.command.PSystemBasicFactory.createSystem(PSystemBasicFactory.java:71)
   at net.sourceforge.plantuml.PSystemBuilder.createPSystem(PSystemBuilder.java:92)
   at net.sourceforge.plantuml.BlockUml.createSystem(BlockUml.java:97)
   at net.sourceforge.plantuml.BlockUml.getSystem(BlockUml.java:87)
   at net.sourceforge.plantuml.BlockUml.getDiagram(BlockUml.java:93)
   at net.sourceforge.plantuml.SourceStringReader.generateImage(SourceStringReader.java:104)
   at net.sourceforge.plantuml.SourceStringReader.generateImage(SourceStringReader.java:90)
   at org.netbeans.modules.plantumlnb.ui.io.PUMLGenerator.generateSVG(PUMLGenerator.java:117)
   at org.netbeans.modules.plantumlnb.ui.PUMLTopComponent$1.run(PUMLTopComponent.java:362)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1432)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2042)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.AssertionError
   at org.openide.util.RequestProcessor.post(RequestProcessor.java:424)
   at org.netbeans.modules.plantumlnb.ui.PUMLTopComponent.setNewContent(PUMLTopComponent.java:351)
   at org.netbeans.modules.plantumlnb.ui.pumlVisualElement$1.run(pumlVisualElement.java:89)
   at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:733)
   at java.awt.EventQueue.access$200(EventQueue.java:103)
   at java.awt.EventQueue$3.run(EventQueue.java:694)
   at java.awt.EventQueue$3.run(EventQueue.java:692)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:703)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)