Patterns of Java Web Application Configuration

Java Web applications are packaged into WAR files and then deployed. Although the vision of WAR files is that they are files that can be deployed on any web server, we have encountered the following limitations

• If you want to add new JDBC drivers or other libraries that need to be visible by classes higher up the application server's classloader hierarchy than the WAR file, you need to exclude these files from the WAR file's lib/ directory, and instead (somehow) get them into the application-server specific lib directory.
• The only official way of configuring the web application is the Web Application Deployment Descriptor. Some tools/processes have existed to dynamically create a web.xml file,
  normally at build time, but possibly at deployment time deployment time.
• Sometimes Post-Installation Configuration File Editing is the solution, which is somewhat low level.
• One alternative used in some projects is Pattern - Hostname-Driven Configuration Files.
• Applications with databases behind them, often use Database-driven webapp configuration

Here is our complete list of web-application configuration patterns 

• Application configuration through JVM properties
• Build-Time Web xml file
• Configuration in Java Source
• Database-driven webapp configuration
• Deploy-Time Web Application creation
• Pattern - Hostname-Driven Configuration Files
• Pattern - In-situ Editing of the Web Application
• Pattern - WAR Files
• Pattern - Web Page configuration GUIs
• Post-Installation Configuration File Editing
• Web Application Deployment Descriptor