Automatic configuration reinitialization in Spring

Question

In Log4j, there is a feature wherein the system can be initialized to do a configure and watch with an interval. This allows for the log4j system to reload its properties wh

Answer 1

I would be extra cautious with reloading spring application context.

What do you expect to happen with singleton beans? If an object has a reference to singleton bean, should it be updated?

Answer 2

If you would like to add context, I have done that in the following way :

public class ApplicationContextUtil
{
   static String[] configFiles = {"applicationContextParent.xml"};

   private static ApplicationContext context = null;

   static
   {
       context = new ClassPathXmlApplicationContext ( configFiles );
   }

   public static void addContext( String[] newConfigFiles )
   {
       // add the new context to the previous context
       ApplicationContext newContext =  new ClassPathXmlApplicationContext ( newConfigFiles, context );
       context = newContext;
   }   
   public static ApplicationContext getApplicationContext ()
   {
       // return the context
       return context;
   }
}

This is your context provider class. For details, you can look at my blog

Answer 3

AFAIK Spring does not provide such a utility. However there is a 3rd party tool, JRebel that enables you to update an entire web application (including the Spring configuration) without requiring a server restart.

A free trial is available, and the purchase price is fairly inexpensive.

Answer 4

I develop using JRebel and I would be very wary of expecting it to refresh your configuration. Works fine with Java, not with Spring though.

Answer 5

I found a utility that does something similar to Log4J here. It's basically an extension to PropertyPlaceholderConfigurer that reloads properties when they change.