List colors = Arrays.asList(new String[] { "Red", "Blue", "Green", "Yellow"});
IModel radioModel = Model.of();
IModel selectModel = Model.of();
add(new RadioChoice("choices", radioModel, colors)
.add(new OnChangeSingleChoiceBehavior()));
add(new DropDownChoice("drpDwnChoices", selectModel, colors)
.add(new OnChangeSingleChoiceBehavior()));
add(new Label("radioModel", radioModel));
add(new Label("selectModel", selectModel));
}