In Adf application we normally used popup.We have one of the property and attribute of popup is contentDelivery .
ContentDelivery attribute of an af:popup component controls the popup initialization time and how does the data get refreshed within the popup. The default content delivery is lazy. This means the content of the popup is not delivered to the client until shown the first time
Good ADF developer should know , when to use what-
immediate — The popup component is added inline within the page when the page is loaded. It does not matter if you do or do not display it, the popup component will always be loaded.
ContentDelivery should be set to immediate if and only if you are absolutely sure that the popup will be invoked at least once. Otherwise you should use the other two values.
Example: If you use a logout logic that needs confirmation than the confirmation popup should be set to immediate.
lazy — The popup component will be loaded (and cached) only when is called for the first time. If you do not explicitly set the ContentDelivery attribute when creating the popup it will implicitly be set to lazy.
This value should be used when dealing with static information(that does not change): warning messages, information messages and so on.
lazyUncached — The popup component will be loaded(but not cached) only when is invoked for the first time; and every time the popup is called it will be reloaded.
This value should be used when dealing with dynamic data.