Java EE 8 Design Patterns and Best Practices

Config

An application's config is everything that varies between different deploys. It can be:

• Hosts, ports, and credentials for database access
• Database schema
• Cache settings
• Hosts, ports, and credentials for accessing message queues

The twelve-factor method requires the separation of config from code. So, the config should never be in the code, because the configs may vary between deploys but the code does not. The practice of placing the config in files, such as Java properties, is not recommended by twelve-factor, as there is always the possibility of placing the same configuration data in different environments (an example is when a developer commits to the version-control repository with its own local configs). Another weakness is ...