EDIT

        UUID taxonUuid = entity.getTaxonUuid();

        config.setAssociatedTaxonUuid(taxonUuid);

        List<SpecimenOrObservationBase> specimens = CdmStore.getService(IOccurrenceService.class).findByTitle(config).getRecords();

        for (SpecimenOrObservationBase<?> specimenOrObservationBase : specimens) {

            specimenUuids.add(specimenOrObservationBase.getUuid());

        }

public class DefaultOpenClassificationWizardHandlerE4 extends DefaultOpenHandlerBaseE4<TaxonNodeDto> {

    @Override

    protected void open(TaxonNodeDto entity, Shell shell, EPartService partService) {

        NewClassificationWizard classificationWizard = new NewClassificationWizard();

        dialog.open();

    }

    @Override

    protected boolean canExecute(Object selection) {

        if (((IStructuredSelection)selection).getFirstElement() instanceof TaxonNodeDto){

            return ((TaxonNodeDto)((IStructuredSelection)selection).getFirstElement()).getTaxonUuid() == null;

        }

        return false;

    }

    public void execute(@Named(IServiceConstants.ACTIVE_SHELL)Shell shell, MHandledMenuItem menuItem,

            EModelService modelService, EPartService partService, MApplication application,

            IEclipseContext context) throws Exception {

        this.context = context;

        this.modelService = modelService;

        this.application = application;