ds0.put(NOTIFY_KEY, NOTIFY_VALUE);
Thread.sleep(5000);
// check the change notification on server0
String type = listener0.getNotificationType();
NotifyData data = (NotifyData)listener0.getNotificationData();
assertTrue("server0: change notification type = " + type, type.equals(DistributedStateUser.NOTIFY_CHANGE));
assertNotNull("server0: change notification data is null", data);
String cat = data.category;
String key = (String)data.key;
String val = (String)data.value;