umldoclet: IllegalStateException at Bibliotekon.getNodeUid(Bibliotekon.java:127)

Expected Behavior

Trying to create Javadoc for the JMRI project. We’ve used the older Plantuml doclet for a long time with Java 8, but now need to work with Java 11 Javadoc.

Actual Behavior

Many, many occurances of

 java.lang.IllegalStateException
  [javadoc] 	at net.sourceforge.plantuml.svek.Bibliotekon.getNodeUid(Bibliotekon.java:127)

Steps to Reproduce the Problem

1. git clone https://github.com/bobjacobsen/JMRI.git
2. git checkout plantUml-update
3. ant plant-uml

Specifications

• Version: 2.0.9 (released Jar file)
• Platform: macOS Mojave
• Java version: 11
• Project link: https://github.com/JMRI/JMRI/ (but the recreating-branch is in https://github.com/bobjacobsen/JMRI )

Traceback:

  [javadoc] java.lang.IllegalStateException
  [javadoc] 	at net.sourceforge.plantuml.svek.Bibliotekon.getNodeUid(Bibliotekon.java:127)
  [javadoc] 	at net.sourceforge.plantuml.cucadiagram.Link.getEntityPort1(Link.java:251)
  [javadoc] 	at net.sourceforge.plantuml.svek.Line.<init>(Line.java:227)
  [javadoc] 	at net.sourceforge.plantuml.svek.GeneralImageBuilder.buildImage(GeneralImageBuilder.java:373)
  [javadoc] 	at net.sourceforge.plantuml.svek.CucaDiagramFileMakerSvek.createFileInternal(CucaDiagramFileMakerSvek.java:102)
  [javadoc] 	at net.sourceforge.plantuml.svek.CucaDiagramFileMakerSvek.createFile(CucaDiagramFileMakerSvek.java:66)
  [javadoc] 	at net.sourceforge.plantuml.cucadiagram.CucaDiagram.exportDiagramInternal(CucaDiagram.java:646)
  [javadoc] 	at net.sourceforge.plantuml.classdiagram.ClassDiagram.exportDiagramInternal(ClassDiagram.java:188)
  [javadoc] 	at net.sourceforge.plantuml.UmlDiagram.exportDiagramNow(UmlDiagram.java:196)
  [javadoc] 	at net.sourceforge.plantuml.AbstractPSystem.exportDiagram(AbstractPSystem.java:130)
  [javadoc] 	at net.sourceforge.plantuml.SourceStringReader.outputImage(SourceStringReader.java:153)
  [javadoc] 	at net.sourceforge.plantuml.SourceStringReader.outputImage(SourceStringReader.java:125)
  [javadoc] 	at nl.talsmasoftware.umldoclet.uml.Diagram.renderDiagramFile(Diagram.java:172)
  [javadoc] 	at nl.talsmasoftware.umldoclet.uml.Diagram.render(Diagram.java:132)
  [javadoc] 	at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
  [javadoc] 	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
  [javadoc] 	at java.base/java.util.Iterator.forEachRemaining(Iterator.java:133)
  [javadoc] 	at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
  [javadoc] 	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
  [javadoc] 	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
  [javadoc] 	at java.base/java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining(StreamSpliterators.java:312)
  [javadoc] 	at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:734)
  [javadoc] 	at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:658)
  [javadoc] 	at nl.talsmasoftware.umldoclet.UMLDoclet.run(UMLDoclet.java:130)
  [javadoc] 	at jdk.javadoc/jdk.javadoc.internal.tool.Start.parseAndExecute(Start.java:582)
  [javadoc] 	at jdk.javadoc/jdk.javadoc.internal.tool.Start.begin(Start.java:431)
  [javadoc] 	at jdk.javadoc/jdk.javadoc.internal.tool.Start.begin(Start.java:344)
  [javadoc] 	at jdk.javadoc/jdk.javadoc.internal.tool.Main.execute(Main.java:63)
  [javadoc] 	at jdk.javadoc/jdk.javadoc.internal.tool.Main.main(Main.java:52)