Java EE部署中的Spring Classloading机制

Question

I would like to understand how ClassLoader of Spring Container.

Here is an example: Deploy a WAR containing all the necessary jars so that Spring Container is started inside the webcontainer of tomcat.

Questions I have:
1. Am I correct in thinking that Spring container classes itself are loaded by the ClassLoader of WAR created by web-container ?
2. When the WAR is undeployed, how are the Class [] (java.lang.Class objects) loaded by the spring container unloaded. Is spring having a classloader to itself ? Or it uses classloader provided by webcontainer ?
3. If my Spring Container is inheriting beans (using parentContextKey in web.xml), and if one of the parent beans has lazy-init=true and is requested by this deployed WAR, who will load and unload the Class object of the requested bean ?

Thanks in advance

Answer 1

All these life cycles is maintained by the container and u make it aware by declaring it in web.xml for example

The RequestContextListener exposes the 'request' scope to the context.
org.springframework.web.context.request.RequestContextListener

And this listener which extends from the container listener, the container is able to handle the lifecycle.

If u have any thing which is lazy init. The web container delegates the call to spring container which search for the class in the classpath.

So essentially the life cycles gets handled. You can also have your own customised listener which handles these life cycles

see if it helps

Answer 2

Your web-app can be based on Spring or simply on JSP&Servlets. And when you run Tomcat or other servlet container then it uses its ClassLoader that load classes and libraries from your WAR which is deployed to webapp folder (for Tomcat).