### Question:
CheckBox extends AbstractField<Boolean> { @Override public boolean isEmpty() { return getValue() == null || getValue().equals(Boolean.FALSE); } CheckBox();  CheckBox(String caption);  CheckBox(String caption, boolean initialState);  CheckBox(String caption, Property<?> dataSource); @Override Class<Boolean> getType(); void addBlurListener(BlurListener listener); void removeBlurListener(BlurListener listener); void addFocusListener(FocusListener listener); void removeFocusListener(FocusListener listener); @Deprecated boolean booleanValue(); @Override void readDesign(Element design, DesignContext designContext); @Override void writeDesign(Element design, DesignContext designContext); @Override void clear(); @Override boolean isEmpty();  }### Answer:
@Test public void initiallyEmpty() { CheckBox tf = new CheckBox(); Assert.assertTrue(tf.isEmpty()); }