Program: 63052
Project: 63052
Buggy source:
protected void actionCreateSubclass(AjaxRequestTarget aTarget,Form<KBConcept> aForm){
  try {
    KnowledgeBase kb=kbModel.getObject();
    KBProperty property=kbService.readProperty(kb,kb.getSubclassIri().stringValue()).get();
    KBHandle propertyHandle=new KBHandle(property.getIdentifier(),property.getName(),property.getDescription());
    List<KBHandle> existingSubclasses=kbService.listChildConcepts(kb,parentConceptHandleModel.getObject().getIdentifier(),true);
    for (    KBHandle subclass : existingSubclasses) {
      if (newSubclassConceptModel.getObject().getName().equals(subclass.getName())) {
        error(new StringResourceModel("String_Node_Str",this).setParameters(subclass.getName(),parentConceptHandleModel.getObject().getUiLabel()).getString());
        aTarget.addChildren(getPage(),IFeedback.class);
        return;
      }
    }
    KBHandle newConceptHandle=kbService.createConcept(kb,newSubclassConceptModel.getObject());
    String parentConceptId=parentConceptHandleModel.getObject().getIdentifier();
    ValueFactory vf=SimpleValueFactory.getInstance();
    KBStatement subclassOfStmt=new KBStatement(newConceptHandle,propertyHandle,vf.createIRI(parentConceptId));
    Reification kbReification=kb.getReification();
    kb.setReification(Reification.NONE);
    kbService.upsertStatement(kb,subclassOfStmt);
    kb.setReification(kbReification);
    send(getPage(),Broadcast.BREADTH,new AjaxConceptSelectionEvent(aTarget,newConceptHandle));
  }
 catch (  QueryEvaluationException|NoSuchElementException e) {
    error("String_Node_Str" + e.getLocalizedMessage());
    LOG.error("String_Node_Str",e);
    aTarget.addChildren(getPage(),IFeedback.class);
  }
  findParent(SubclassCreationDialog.class).close(aTarget);
}

Fixed version (ground truth):
protected void actionCreateSubclass(AjaxRequestTarget aTarget,Form<KBConcept> aForm){
  try {
    KnowledgeBase kb=kbModel.getObject();
    KBProperty property=kbService.readProperty(kb,kb.getSubclassIri().stringValue()).get();
    KBHandle propertyHandle=new KBHandle(property.getIdentifier(),property.getName(),property.getDescription());
    List<KBHandle> existingSubclasses=kbService.listChildConcepts(kb,parentConceptHandleModel.getObject().getIdentifier(),true);
    for (    KBHandle subclass : existingSubclasses) {
      if (newSubclassConceptModel.getObject().getName().equals(subclass.getName())) {
        error(new StringResourceModel("String_Node_Str",this).setParameters(subclass.getName(),parentConceptHandleModel.getObject().getUiLabel()).getString());
        aTarget.addChildren(getPage(),IFeedback.class);
        return;
      }
    }
    KBHandle newConceptHandle=kbService.createConcept(kb,newSubclassConceptModel.getObject());
    String parentConceptId=parentConceptHandleModel.getObject().getIdentifier();
    ValueFactory vf=SimpleValueFactory.getInstance();
    KBStatement subclassOfStmt=new KBStatement(newConceptHandle,propertyHandle,vf.createIRI(parentConceptId));
    Reification kbReification=kb.getReification();
    kb.setReification(Reification.NONE);
    kbService.upsertStatement(kb,subclassOfStmt);
    kb.setReification(kbReification);
    send(getPage(),Broadcast.BREADTH,new AjaxConceptSelectionEvent(aTarget,newConceptHandle,true));
  }
 catch (  QueryEvaluationException|NoSuchElementException e) {
    error("String_Node_Str" + e.getLocalizedMessage());
    LOG.error("String_Node_Str",e);
    aTarget.addChildren(getPage(),IFeedback.class);
  }
  findParent(SubclassCreationDialog.class).close(aTarget);
}