Hooks
Hook is a plugin type and is the preferred way to customize the portal core features. Hooks are hot deployable and more forward compatible, filling a wide variety of the common needs for overriding the portal core functionality. Thus, whenever possible, hooks should be used in place of Ext plugins. Common scenarios which require the use of a hook are the need to perform custom actions on portal startup or user login, overwrite or extend portal JSPs, modify portal properties, replace a portal service with a custom implementation, modify search summaries, queries, and indexes, override struts actions, modify servlet filters and mappings, and so on.
In summary, there are several kinds of hooks: portal properties hooks, language properties hooks, custom JSP hooks, indexer post processor hooks, service wrapper hooks, servlet filters and servlets mapping hooks, and struts actions hooks.
Hook plugin project default template
Liferay plugins SDK provides a hook plugin project default...