### Question:
StringFormFieldController extends FormFieldController<String> { @Override public void initialize() { validateValueOnChange(); }  @Override void initialize(); abstract ObservableValue<String> getObservableValue(); @Override String getFieldValue();  }### Answer:
@Test public void validatesOnEveryPropertyChangeByDefault() { sampleFieldController.initialize(); assertThat(validationCount.get()).isEqualTo(0); sampleProp.setValue("new value"); assertThat(validationCount.get()).isEqualTo(1); }