• Spring  is
    • open source
    • light weight
    • loosely coupled
    • aspect oriented
    • dependency injection
  • Spring is used to develop java/j2ee application having the capabilities enterprise application
  • The spring application that deals with large scale, heavy weight and complex business logic(main logic)is called an enterprise application
    • Eg: credit cart/debit card application

Note:-
Web container/ Servlet container and Ejb container are heavy weight container because they use lot of memory and they need to be started separately by activating web server and application server s/w

FAQ:

How can you say spring is lightweight s/w?
  • In spring s/w containers are predefined classes, not the separate s/w to install by creating objects. For these classes we can activate spring container. So spring container are called light weight container
  • To develop various resource of spring application is the form of user defined classes and interface, there is no necessity of working with spring Api
  • This makes spring application resources as Spring API independent, pojo’s (plan old java objects) and poji’s (plan old java interfaces).

 What is pojo and poji
·        While developing a userdefined class as resource of certain technology based application if that class is not extending from predefined of technology api or not implementing predefind interface of technology api then it is called pojo
·        Example , while developing java class for spring applcition if that class is not extending from predefine spring api class and not implementing predefined spring interface then it is class pojo class
·        While developing an interface as the resource of the application based on certain technology if that interface is not extending from any predefined interface of that technology api then that interface is called poji