The compilation of XtxtUML xtend files fails with NullPointerException

[kovacsgabor]

Running txtUML in a runtime Eclipse produces the following errors:

(All NullPointerExceptions occurred at the same line, I only copied the first stack trace.)

1 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link10/hu/elte/txtuml/xtxtuml/formatting/XtxtUMLFormatter.xtend'.
java.lang.NullPointerException
at org.eclipse.core.runtime.Path.append(Path.java:261)
at org.eclipse.xtext.builder.JDTAwareEclipseResourceFileSystemAccess2.addToSourceFolders(JDTAwareEclipseResourceFileSystemAccess2.java:66)
at org.eclipse.xtend.ide.builder.SourceRelativeFileSystemAccess.ensureOutputConfigurationDirectoryExists(SourceRelativeFileSystemAccess.java:29)
at org.eclipse.xtext.builder.EclipseResourceFileSystemAccess2.generateFile(EclipseResourceFileSystemAccess2.java:259)
at org.eclipse.xtext.generator.AbstractFileSystemAccess2.generateFile(AbstractFileSystemAccess2.java:28)
at org.eclipse.xtext.builder.ParallelFileSystemAccess$7.apply(ParallelFileSystemAccess.java:141)
at org.eclipse.xtext.builder.ParallelFileSystemAccess$7.apply(ParallelFileSystemAccess.java:1)
at org.eclipse.xtext.builder.ParallelFileSystemAccess$1.apply(ParallelFileSystemAccess.java:57)
at org.eclipse.xtext.builder.ParallelBuilderParticipant.doBuild(ParallelBuilderParticipant.java:128)
at org.eclipse.xtext.builder.BuilderParticipant.build(BuilderParticipant.java:221)
at org.eclipse.xtext.builder.impl.RegistryBuilderParticipant$DeferredBuilderParticipant.build(RegistryBuilderParticipant.java:161)
at org.eclipse.xtext.builder.impl.RegistryBuilderParticipant.build(RegistryBuilderParticipant.java:69)
at org.eclipse.xtext.builder.impl.XtextBuilder.doBuild(XtextBuilder.java:252)
at org.eclipse.xtext.builder.impl.XtextBuilder.fullBuild(XtextBuilder.java:280)
at org.eclipse.xtext.builder.impl.XtextBuilder.build(XtextBuilder.java:117)
at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:734)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:206)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:246)
at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:299)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:302)
at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:358)
at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:381)
at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:143)
at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:241)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)
14 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link11/hu/elte/txtuml/xtxtuml/ui/labeling/XtxtUMLDescriptionLabelProvider.xtend'.
java.lang.NullPointerException
...
16 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link11/hu/elte/txtuml/xtxtuml/ui/contentassist/XtxtUMLProposalProvider.xtend'.
java.lang.NullPointerException
...
33 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link10/hu/elte/txtuml/xtxtuml/typesystem/XtxtUMLEarlyExitComputer.xtend'.
java.lang.NullPointerException
...
35 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link10/hu/elte/txtuml/xtxtuml/scoping/XtxtUMLImplicitlyImportedFeatures.xtend'.
java.lang.NullPointerException
...
37 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link11/hu/elte/txtuml/xtxtuml/ui/outline/XtxtUMLOutlineTreeProvider.xtend'.
java.lang.NullPointerException
...
177 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link11/hu/elte/txtuml/xtxtuml/ui/quickfix/XtxtUMLQuickfixProvider.xtend'.
java.lang.NullPointerException
...
181 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link10/hu/elte/txtuml/xtxtuml/jvmmodel/XtxtUMLJvmModelInferrer.xtend'.
java.lang.NullPointerException
...
182 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link10/hu/elte/txtuml/xtxtuml/validation/XtxtUMLValidator.xtend'.
java.lang.NullPointerException
...
188 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link10/hu/elte/txtuml/xtxtuml/scoping/XtxtUMLXImportSectionNamespaceScopeProvider.xtend'.
java.lang.NullPointerException
...
191 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link10/hu/elte/txtuml/xtxtuml/naming/XtxtUMLQualifiedNameConverter.xtend'.
java.lang.NullPointerException
...
193 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link10/hu/elte/txtuml/xtxtuml/compiler/XtxtUMLCompiler.xtend'.
java.lang.NullPointerException
...
203 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link11/hu/elte/txtuml/xtxtuml/ui/highlighting/XtxtUMLHighlightingCalculator.xtend'.
java.lang.NullPointerException
...
205 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link10/hu/elte/txtuml/xtxtuml/typesystem/XtxtUMLTypeComputer.xtend'.
java.lang.NullPointerException
...
221 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link9/hu/elte/txtuml/xtxtuml/lib/std.xtend'.
java.lang.NullPointerException
...
222 [Worker-5] ERROR org.eclipse.xtext.builder.BuilderParticipant - Error during compilation of 'platform:/resource/.org.eclipse.jdt.core.external.folders/.link11/hu/elte/txtuml/xtxtuml/ui/labeling/XtxtUMLLabelProvider.xtend'.
java.lang.NullPointerException
...

[kovacsgabor]

Deleting and recreating my workspace solved the problem.