Spring Framework - Overview

Spring is the most popular application development framework for enterprise Java. Millions of developers around the world use Spring Framework to create high performing, easily testable, reusable code.

Spring Framework - Architecture

Spring could potentially be a one-stop shop for all your enterprise applications, however, Spring is modular, allowing you to pick and choose which modules are applicable to you, without having to bring in the rest. Following section gives detail about all the modules available in Spring Framework.

Spring - Environment Setup

This tutorial will guide you on how to prepare a development environment to start your work with Spring Framework. This tutorial will also teach you how to setup JDK, Tomcat and Eclipse on your machine before you setup Spring Framework:

Spring - Hello World Example

Let us start actual programming with Spring Framework. Before you start writing your first example using Spring framework, you have to make sure that you have setup your Spring environment properly as explained in Spring - Environment Setup tutorial.

Spring - IoC Containers

The Spring container is at the core of the Spring Framework. The container will create the objects, wire them together, configure them, and manage their complete lifecycle from creation till destruction.

Spring - Bean Definition

The objects that form the backbone of your application and that are managed by the Spring IoC container are called beans. A bean is an object that is instantiated, assembled, and otherwise managed by a Spring IoC container.

Spring - Bean Scopes

When defining a <bean> in Spring, you have the option of declaring a scope for that bean. For example, To force Spring to produce a new bean instance each time one is needed, you should declare the bean's scope attribute to be prototype. Similar way if you want Spring to return the same bean instance each time one is needed, you should declare the bean's scope attribute to be singleton.

Spring - Bean Life Cycle

The life cycle of a Spring bean is easy to understand. When a bean is instantiated, it may be required to perform some initialization to get it into a usable state. Similarly, when the bean is no longer required and is removed from the container, some cleanup may be required.

Spring - Bean Post Processors

The BeanPostProcessor interface defines callback methods that you can implement to provide your own instantiation logic, dependency-resolution logic etc. You can also implement some custom logic after the Spring container finishes instantiating, configuring, and initializing a bean by plugging in one or more BeanPostProcessor implementations.

Spring - Bean Definition Inheritance

A bean definition can contain a lot of configuration information, including constructor arguments, property values, and container-specific information such as initialization method, static factory method name, and so on.

Spring - Dependency Injection

Every java based application has a few objects that work together to present what the end-user sees as a working application.

Spring - Injecting Inner Beans

As you know Java inner classes are defined within the scope of other classes, similarly, inner beans are beans that are defined within the scope of another bean. Thus, a <bean/> element inside the <property/> or <constructor-arg/> elements is called inner bean and it is shown below.

Spring - Injecting Collection

You have seen how to configure primitive data type using value attribute and object references using ref attribute of the <property> tag in your Bean configuration file. Both the cases deal with passing singular value to a bean.

Spring - Beans Auto-Wiring

You have learnt how to declare beans using the <bean> element and inject <bean> with using <constructor-arg> and <property> elements in XML configuration file.

Spring - Annotation Based Configuration

Starting from Spring 2.5 it became possible to configure the dependency injection using annotations. So instead of using XML to describe a bean wiring, you can move the bean configuration into the component class itself by using annotations on the relevant class, method, or field declaration.

Spring - Java Based Configuration

So far you have seen how we configure Spring beans using XML configuration file. If you are comfortable with XML configuration, then I will say it is really not required to learn how to proceed with Java based configuration because you are going to achieve the same result using either of the configurations available.

Event Handling in Spring

You have seen in all the chapters that core of Spring is the ApplicationContext, which manages complete life cycle of the beans. The ApplicationContext publishes certain types of events when loading the beans. For example, a ContextStartedEvent is published when the context is started and ContextStoppedEvent is published when the context is stopped.

Custom Events in Spring

There are number of steps to be taken to write and publish your own custom events. Follow the instructions given in this chapter to write, publish and handle Custom Spring Events.

AOP with Spring Framework

One of the key components of Spring Framework is the Aspect oriented programming (AOP) framework. Aspect Oriented Programming entails breaking down program logic into distinct parts called so-called concerns.

Spring - JDBC Framework Overview

While working with database using plain old JDBC, it becomes cumbersome to write unnecessary code to handle exceptions, opening and closing database connections etc. But Spring JDBC Framework takes care of all the low-level details starting from opening the connection, prepare and execute the SQL statement, process exceptions, handle transactions and finally close the connection.