public IMySearchForm getSearchForm() {
  return (IMySearchForm) getSearchFormInternal();
}

@ClassId("42f088a6-d93a-41cc-b6fd-2fc780494fd0")
public class PersonTablePage extends AbstractPersonTablePage<Table> {
  ...

  @Override
  protected void execPopulateTable() {
    getTable().replaceRows(BEANS.get(IPersonService.class)
        .findPersons(new PersonSearchQuery().withFirstName(getSearchFormInternal().getFirstNameField().getValue()))
        .stream().map(person -> {
          ITableRow row = getTable().createRow();
          row.getCellForUpdate(getTable().getIdColumn()).setValue(person.getId());
          row.getCellForUpdate(getTable().getFirstNameColumn()).setValue(person.getFirstName());
          row.getCellForUpdate(getTable().getLastNameColumn()).setValue(person.getLastName());
          return row;
        }).collect(Collectors.toList()));
  }

  @Override
  protected Class<? extends ISearchForm> getConfiguredSearchForm() {
    return PersonSearchForm.class;
  }

  @Override
  public PersonSearchForm getSearchFormInternal() {
    return (PersonSearchForm) super.getSearchFormInternal();
  }
  ...
}