Class IntrospectorCleanupListener

  extended by org.springframework.web.util.IntrospectorCleanupListener
All Implemented Interfaces:
EventListener, ServletContextListener

public class IntrospectorCleanupListener
extends Object
implements ServletContextListener

Listener that flushes the JavaBeans Introspector cache on web app shutdown. Register this listener in your web.xml to guarantee proper release of the web app class loader and the classes that it holds.

If the JavaBeans Introspector has been used to analyze application classes, the Introspector cache will hold a hard reference to those classes. Consequently, those classes and the web app class loader will not be garbage collected on web app shutdown!

Unfortunately, the only way to clean up the Introspector is to flush the entire cache, as there is no way to specifically determine the application's classes referenced there. This will remove cached introspection results for all other applications in the server too.

Note that this listener is not necessary when using Spring's beans infrastructure, as Spring's own introspection results cache will immediately flush an analyzed class from the JavaBeans Introspector cache.

Application classes hardly ever need to use the JavaBeans Introspector directly, so are normally not the cause of Introspector resource leaks. Rather, many libraries and frameworks do not clean up the Introspector, for example Struts and Quartz.

Note that a single such Introspector leak will cause the entire web app class loader to not get garbage collected! This has the consequence that you will see all the application's static class resources (like singletons) around after web app shutdown, which is not the fault of those classes!

Juergen Hoeller
See Also:

Constructor Summary
Method Summary
 void contextDestroyed(ServletContextEvent event)
 void contextInitialized(ServletContextEvent event)
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail


public IntrospectorCleanupListener()
Method Detail


public void contextInitialized(ServletContextEvent event)
Specified by:
contextInitialized in interface ServletContextListener


public void contextDestroyed(ServletContextEvent event)
Specified by:
contextDestroyed in interface ServletContextListener

Copyright (c) 2002-2007 The Spring Framework Project.