Liferay Plugins

There are different types of plugins available,

1. Portlet
2. Layout Template
3. Theme
4. Hook
5. Ext(Extension)
6. Web Content
7. Service Builder

Theme                 :- It helps to maintain Look & feel of  Liferay portal. 

Hook                  :- Is Used to customise core functionality of liferay.
Service Builder    :- A tool which is generally used to generate code to interact with database
Ext                 :-This is also used to customize core functionalitly.Hooks having some                 limitation beyond that we haveto use ext.if we use ext                                                   restart  would  be required.