public AjaxResponse enableDnD(AjaxActionEvent event) {
// Make the draggable:
Draggable action1 = new Draggable("draggable");
action1.addOption("revert", true);
// Add the droppable:
AddDroppable action2 = new AddDroppable("droppable");
action2.addOption("onDrop", "function(draggable, droppable) { showAlertOnDrop(draggable, droppable); }");
// Create a concrete ajax response:
AjaxResponse response = new AjaxResponseImpl();
// Add the actions:
response.addAction(action1);