when can we use hoooks?

Hook plugins can be used to modify portal properties or to perform custom actions on startup,
shutdown, login, logout, session creation and session destruction.


Using service wrappers, it is possible for a hook plugin to replace any of the core Liferay services
with a custom implementation.


Hook plugins can also replace the JSP templates used by any of the default portlets, allowing you to customize their appearance as desired

RenderResponse  extends MimeResponse 


MimeResponse extends PortletResponse

PortletResponse is an interface in Portlet API

what are the attributes of actionURL and renderURL tags?

what are the different actions available in portlet tags?

what are the Objects created by tag?

Portlet API 2.0 defines<portlet:defineObjects />

It creates useful objects in JSP page

•  renderRequest,
• renderResponse
• portletConfig

Can you list some methods from PortletContext?

The PortletContext interface defines a portlet view of the portlet container. The PortletContext also makes resources available to the portlet. Using the context, a portlet can access the portlet log, and obtain URL references to resources.

Method Summary
java.lang.Object	getAttribute(java.lang.String name)           Returns the portlet container attribute with the given name, or null if there is no attribute by that name.
java.util.Enumeration<java.lang.String>	getAttributeNames()           Returns an Enumeration containing the attribute names available within this portlet context, or an empty Enumeration if no attributes are available.
java.util.Enumeration<java.lang.String>	getContainerRuntimeOptions()           Returns the container container runtime options keys supported by this portlet container.
java.lang.String	getInitParameter(java.lang.String name)           Returns a String containing the value of the named context-wide initialization parameter, or null if the parameter does not exist.
java.util.Enumeration<java.lang.String>	getInitParameterNames()           Returns the names of the context initialization parameters as an Enumeration of String objects, or an empty Enumeration if the context has no initialization parameters.

java.lang.String	getRealPath(java.lang.String path)           Returns a String containing the real path for a given virtual path.
PortletRequestDispatcher	getRequestDispatcher(java.lang.String path)           Returns a PortletRequestDispatcher object that acts as a wrapper for the resource located at the given path.
java.net.URL	getResource(java.lang.String path)           Returns a URL to the resource that is mapped to a specified path.
java.io.InputStream	getResourceAsStream(java.lang.String path)           Returns the resource located at the given path as an InputStream object.

what are the useful methods in PortletConfig?