Spring Briefly

About:

Spring Framework was created by Rod Johnson (2003) and released under Apache 2.0 license. The most popular application development framework for enterprise Java Provides to create high performing, easily testable and reusable code.

Spring-1:

Enables Plain Old Java Object (POJO) based programming model  with POJO you don’t need EJB container product  utilizes existing technologies like ORM frameworks logging frameworks  JEE, Quartz, JDK timers.

Spring-2:

It is a well-designed web model-view-controller (MVC) framework (a great alternative to Struts) provides a coherent transaction management interface that be applicable to a local transactions () local transactions or global transactions (JTA) provides a suitable API for translating technology-specific exceptions (for instance, thrown by JDBC, Hibernate, or JDO,) into consistent, unchecked exceptions. The Inversion of Control (IoC) containers are lightweight, especially when compared to EJB containers. Being lightweight is beneficial for developing and deploying applications on computers with limited resources (RAM&CPU).   Testing is simple because environment-dependent code is moved into this framework.

Beans?

In spring, POJO’s (plain old java object) are called ‘beans’ and those objects instantiated, managed, created by Spring IoC container. Beans are created with the configuration metadata (XML file) that we supply to the container.  Bean definition contains configuration metadata. With this information container knows how to create bean, beans lifecycle, beans dependencies   After specifying objects of an application, instances of those objects will be reached by getBean() method. Spring supports given scope types for beans:

  Singleton (a single instance per Spring IoC container (default))

  Prototype

  Request

  Session

  Global-session

The BeanFactory interface provides an advanced high level configuration mechanism capable of managing any type of objects. BeanFactory provides configuration level basic functionality for IoC implementation.
ApplicationContext is a sub-interface that is built on BeanFactory, it provides application level context to be used in Spring web applications. ApplicationContext is a complete super-set of BeanFactory and any functionality provided by BeanFactory is also available in ApplicationContext.
Spring configuration contains at least one bean definition that the container must manage. These beans are declared under .. tags and all beans resides under .. tags.

Packages, Classes and Interfaces (Spring IoC):

org.springframework.beans and org.springframework.context are two packages that contains basic functionality of Spring’s IoC.

Configuring Beans:

IoC container consumes some sort of configuration mostly in the form of XML, this configuration tells the container a way in which the objects are to be instantiated, configured and managed in the application.