What is the most common standard in a Java web app for including resources on the classpath?

Question

I'm using internationalization with Spring, and the properties file needs to be on the classpath. I also have some XML files that will need to be on the classpath. Is it acceptable to just include those resources inside the "src" in a sub-directory, and then let them build to the classpath, or is it better to add a different folder to the classpath during startup? I'm using Ant, but from the looks of it this was the approach Maven took (everything under src or test). I'm looking for the most widely accepted industry standards or better alternatives. Thanks!

Answer 1

Is it acceptable to just include those resources inside the "src" in a sub-directory, and then let them build to the classpath

Depends on the sole purpose of the resource in question. With this approach, any minor edit in such a resource file would thus require a full rebuild, redeploy and restart.

This may not necessarily harm for one-time-read startup and applicationwide configuration files like web.xml and application.xml and consorts since that would usually affect (or be affected by) changes in Java source code which require a full rebuild/redeploy/etc anyway.

But in case of runtime files like i18n properties files and environment-specific configuration files (which would/could be managed by a non-developer like a serveradmin or a customer), it is not useful to package it inside the webapplication. This requires knowledge how to rebuild the webapp after edits. You would rather like to externalize it so that only a webapp restart is required to reflect the changes in the configuration, or maybe even not at all, like for ResourceBundle which will just reload automagically.

I myself usually put such files in a fixed path along the servletcontainer and add that path to the servletcontainer's runtime classpath. In case of for example Tomcat, it's configureable as shared.loader property in /conf/catalina.properties . Eg

shared.loader=/var/webapp

Anything in this folder is then taken in the servletcontainer's (and webapp's) runtime classpath.

Answer 2

Anything you put in your WEB-INF/classes directory is automatically in the CLASSPATH.

I usually put only .java files under /src and /test directories. Any resources that I put elsewhere have to end up in WEB-INF/classes. It's either my IDE (IntelliJ) or Ant that put them there when the WAR file is created.

I would recommend following the Spring examples and put resources where they do.

For example, if you use Velocity as your templating engine, you'll see that Spring configuration allows you to put them under /WEB-INF/vm_views.

Properties are put in WEB-INF/classes.

Check the Spring docs for examples.