Python4capella installation issue with Capella 7.0.1

LSP · 29 April 2026 11:21

Hello, I’m trying to install Python4capella on Capella 7.0.1. For that, I have followed the Installation section in GitHub - labs4capella/python4capella: Python for Capella · GitHub . Once the addon is installed and Capella restarted, I cannot see diagrams any more. Instead this error is reported:

com.google.common.util.concurrent.ExecutionError: java.lang.ExceptionInInitializerError at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2053) at com.google.common.cache.LocalCache.get(LocalCache.java:3966) at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3989) at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4950) at org.eclipse.sirius.common.acceleo.aql.business.internal.AQLSiriusInterpreter.evaluateExpression(AQLSiriusInterpreter.java:216) at org.eclipse.sirius.common.acceleo.aql.business.internal.AQLSiriusInterpreter.evaluate(AQLSiriusInterpreter.java:197) at org.eclipse.sirius.tools.internal.interpreter.SessionInterpreter.evaluate(SessionInterpreter.java:179) at org.eclipse.sirius.common.tools.api.interpreter.IInterpreter.evaluateCollection(IInterpreter.java:148) at org.eclipse.sirius.diagram.tools.internal.management.ToolFilterDescriptionListenerForUpdate.elementsToListen(ToolFilterDescriptionListenerForUpdate.java:150) at org.eclipse.sirius.diagram.tools.internal.management.ToolFilterDescriptionListenerForUpdate.getFilter(ToolFilterDescriptionListenerForUpdate.java:133) at org.eclipse.sirius.diagram.tools.internal.management.ToolFilterDescriptionListenerForUpdate.(ToolFilterDescriptionListenerForUpdate.java:73) at org.eclipse.sirius.diagram.tools.internal.management.ToolFilterDescriptionListenersManager.getToolFilterDescriptionListener(ToolFilterDescriptionListenersManager.java:97) at org.eclipse.sirius.diagram.tools.internal.management.ToolFilterDescriptionListenersManager.addListenersForFilters(ToolFilterDescriptionListenersManager.java:79) at org.eclipse.sirius.diagram.tools.api.management.ToolManagement.updateFilters(ToolManagement.java:572) at org.eclipse.sirius.diagram.tools.api.management.ToolManagement.updateFilters(ToolManagement.java:574) at org.eclipse.sirius.diagram.tools.api.management.ToolManagement.addVSMToolsForDiagramWithLayer(ToolManagement.java:479) at org.eclipse.sirius.diagram.tools.api.management.ToolManagement.addVSMTools(ToolManagement.java:536) at org.eclipse.sirius.diagram.tools.api.management.ToolManagement.computeAvailableTools(ToolManagement.java:284) at org.eclipse.sirius.diagram.tools.api.management.ToolManagement.updateTools(ToolManagement.java:223) at org.eclipse.sirius.diagram.tools.internal.management.UpdateToolRecordingCommand.doExecute(UpdateToolRecordingCommand.java:59) at org.eclipse.emf.transaction.RecordingCommand.execute(RecordingCommand.java:130) at org.eclipse.sirius.diagram.ui.tools.internal.editor.DDiagramEditorSessionListenerDelegate.reloadPalette(DDiagramEditorSessionListenerDelegate.java:262) at org.eclipse.sirius.diagram.ui.tools.internal.editor.DDiagramEditorSessionListenerDelegate.run(DDiagramEditorSessionListenerDelegate.java:193) at org.eclipse.sirius.diagram.ui.tools.internal.editor.DDiagramEditorImpl.notify(DDiagramEditorImpl.java:1340) at org.eclipse.sirius.diagram.ui.tools.internal.editor.DDiagramEditorImpl.setInput(DDiagramEditorImpl.java:1936) at org.eclipse.gef.ui.parts.GraphicalEditor.init(GraphicalEditor.java:345) at org.eclipse.gmf.runtime.diagram.ui.parts.DiagramEditor.init(DiagramEditor.java:657) at org.eclipse.gmf.runtime.diagram.ui.resources.editor.parts.DiagramDocumentEditor.init(DiagramDocumentEditor.java:129) at org.eclipse.sirius.diagram.ui.tools.internal.editor.DDiagramEditorImpl.init(DDiagramEditorImpl.java:572) at org.eclipse.ui.internal.EditorReference.initialize(EditorReference.java:353) at org.eclipse.ui.internal.e4.compatibility.CompatibilityPart.create(CompatibilityPart.java:344) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:569) at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:58) at org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(InjectorImpl.java:995) at org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(InjectorImpl.java:960) at org.eclipse.e4.core.internal.di.InjectorImpl.internalInject(InjectorImpl.java:140) at org.eclipse.e4.core.internal.di.InjectorImpl.internalMake(InjectorImpl.java:403) at org.eclipse.e4.core.internal.di.InjectorImpl.make(InjectorImpl.java:330) at org.eclipse.e4.core.contexts.ContextInjectionFactory.make(ContextInjectionFactory.java:202) at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.createFromBundle(ReflectionContributionFactory.java:91) at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.doCreate(ReflectionContributionFactory.java:60) at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.create(ReflectionContributionFactory.java:42) at org.eclipse.e4.ui.workbench.renderers.swt.ContributedPartRenderer.createWidget(ContributedPartRenderer.java:132) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createWidget(PartRenderingEngine.java:995) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:659) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:763) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:728) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:712) at org.eclipse.e4.ui.workbench.renderers.swt.StackRenderer.showTab(StackRenderer.java:1208) at org.eclipse.e4.ui.workbench.renderers.swt.LazyStackRenderer.postProcess(LazyStackRenderer.java:116) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:677) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:763) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:728) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:712) at org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:72) at org.eclipse.e4.ui.workbench.renderers.swt.SashRenderer.processContents(SashRenderer.java:150) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:673) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:763) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:728) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:712) at org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:72) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:673) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$1.run(PartRenderingEngine.java:544) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:528) at org.eclipse.e4.ui.workbench.renderers.swt.ElementReferenceRenderer.createWidget(ElementReferenceRenderer.java:73) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createWidget(PartRenderingEngine.java:995) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:659) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:763) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:728) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:712) at org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:72) at org.eclipse.e4.ui.workbench.renderers.swt.SashRenderer.processContents(SashRenderer.java:150) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:673) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:763) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:728) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:712) at org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:72) at org.eclipse.e4.ui.workbench.renderers.swt.SashRenderer.processContents(SashRenderer.java:150) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:673) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:763) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:728) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:712) at org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:72) at org.eclipse.e4.ui.workbench.renderers.swt.PerspectiveRenderer.processContents(PerspectiveRenderer.java:51) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:673) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:763) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:728) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:712) at org.eclipse.e4.ui.workbench.renderers.swt.PerspectiveStackRenderer.showTab(PerspectiveStackRenderer.java:82) at org.eclipse.e4.ui.workbench.renderers.swt.LazyStackRenderer.postProcess(LazyStackRenderer.java:116) at org.eclipse.e4.ui.workbench.renderers.swt.PerspectiveStackRenderer.postProcess(PerspectiveStackRenderer.java:64) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:677) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:763) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:728) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:712) at org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:72) at org.eclipse.e4.ui.workbench.renderers.swt.SashRenderer.processContents(SashRenderer.java:150) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:673) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:763) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:728) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:712) at org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:72) at org.eclipse.e4.ui.workbench.renderers.swt.WBWRenderer.processContents(WBWRenderer.java:658) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:673) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:763) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:728) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:712) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1083) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1046) at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:155) at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:643) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:550) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:171) at org.polarsys.capella.core.platform.sirius.ui.app.CapellaApplication.start(CapellaApplication.java:118) at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:203) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:136) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:402) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:255) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:569) at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:659) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:596) at org.eclipse.equinox.launcher.Main.run(Main.java:1467) Caused by: java.lang.ExceptionInInitializerError at org.eclipse.acceleo.query.runtime.impl.QueryBuilderEngine.build(QueryBuilderEngine.java:70) at org.eclipse.sirius.common.acceleo.aql.business.internal.AQLSiriusInterpreter$4.load(AQLSiriusInterpreter.java:163) at org.eclipse.sirius.common.acceleo.aql.business.internal.AQLSiriusInterpreter$4.load(AQLSiriusInterpreter.java:1) at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3533) at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2282) at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2159) at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2049) … 141 more Caused by: java.lang.UnsupportedOperationException: java.io.InvalidClassException: org.antlr.v4.runtime.atn.ATN; Could not deserialize ATN with version 3 (expected 4). at org.antlr.v4.runtime.atn.ATNDeserializer.deserialize(ATNDeserializer.java:56) at org.antlr.v4.runtime.atn.ATNDeserializer.deserialize(ATNDeserializer.java:48) at org.eclipse.acceleo.query.parser.QueryLexer.(QueryLexer.java:287) … 148 more Caused by: java.io.InvalidClassException: org.antlr.v4.runtime.atn.ATN; Could not deserialize ATN with version 3 (expected 4). … 151 more

Do you have any idea about what I can do?

Thanks!

juancar95 · 29 April 2026 20:25

Hello Laura,

I’d say what you’re experiencing is a version conflict with ANTLR inside Capella, not an issue with Python4Capella itself. To narrow it down, I’d need two things from your installation:

Go to Help → About → Installation Details → Installed Software so we can see the exact version of Python4Capella you have and what other features are installed.
Start Capella with -console -consoleLog and, in the OSGi console, run ss antlr and paste the output. That will list all resolved ANTLR bundles and show us which version is the “intruder.”

In the meantime, here’s something you can try to recover the diagrams and confirm the direction:

Go to Help → About → Installation Details → Installation History, revert to the snapshot prior to P4C, and restart. If the diagrams come back, that confirms the conflicting dependency was introduced with that installation.

Then reinstall P4C via Help → Install New Software… pointing to the update site zip, and start Capella with -clean so the OSGi cache is rebuilt.

With the output of ss antlr and the Installed Software list, I can tell you exactly which feature to remove or replace.

Best regards.

LSP · 30 April 2026 06:01

Hello and thanks for your help!

You can see here the installation details and the OSGi console output:

On the other hand, I have reverted the installation to the snapshot prior of P4C and so I can see the diagrams well.

Thanks!