      /**
       * The constants used in this Content Widget.
       */
      public static interface CwConstants extends Constants,
          ContentWidget.CwConstants {
        String cwCheckBoxCheckAll();

        String cwCheckBoxDescription();

        String cwCheckBoxFemale();

        String cwCheckBoxMale();

        String cwCheckBoxName();

        String cwCheckBoxUnknown();
      }

      /**
       * An instance of the constants.
       */
      private CwConstants constants;

      /**
       * Initialize this example.
       */
      @Override
      public Widget onInitialize() {
        // Create a vertical panel to align the check boxes
        VerticalPanel vPanel = new VerticalPanel();
        HTML label = new HTML(constants.cwCheckBoxCheckAll());
        label.ensureDebugId("cwCheckBox-label");
        vPanel.add(label);

        // Add a male checkbox
        CheckBox maleCheckBox = new CheckBox(constants.cwCheckBoxMale());
        maleCheckBox.ensureDebugId("cwCheckBox-male");
        vPanel.add(maleCheckBox);

        // Add a female checkbox
        CheckBox femaleCheckBox = new CheckBox(constants.cwCheckBoxFemale());
        femaleCheckBox.ensureDebugId("cwCheckBox-female");
        vPanel.add(femaleCheckBox);

        // Add one disabled checkbox
        CheckBox disabledCheckBox = new CheckBox(constants.cwCheckBoxUnknown());
        disabledCheckBox.ensureDebugId("cwCheckBox-disabled");
        disabledCheckBox.setEnabled(false);
        vPanel.add(disabledCheckBox);

        // Return the panel of checkboxes
        return vPanel;
      }