June 21, 2022 Product Announcement Developers Urban Malc
KumuluzEE Java EE Microservices

Announcing KumuluzEE 4.1.0 release - with improvements to the configuration framework!

We are announcing the availability of KumuluzEE version 4.1.0.

This release brings improvements to the configuration framework, such as configuration profiles, improved variable interpolation, and more!

Configuration profiles can be used to define plug-in configuration fragments, that can be turned on or off at the deployment time. The fragments can define new configuration values or override existing ones in config.yml file. Let’s look at an example defining the profile live. Start by defining the config.yml file as usual:


    url: http://localhost:8081

Now let’s define the live profile fragment:


    url: http://customer-service.example.com:8081

When deploying the service, the profile can be activated by setting the configuration value kumuluzee.config.profile to live, for example add the environment variable:


Multiple configuration profiles can be activated by setting the configuration value kumuluzee.config.profile as CSV. When overriding values, the last defined profile has the largest priority. For example: KUMULUZEE_CONFIG_PROFILE=docker,live.

The configuration profiles mechanism is generic and can be used to alter the behavior of your custom ConfigurationSource implementations by implementing the initProfile(String profileName) function of the interface. The interface now also defines the default implementations of converter functions, which makes implementing custom configuration sources easier and avoids duplication of implementations when the backing configuration source returns only String values.

Another improvement added in this release is the support for nested value interpolation and support for default values when using value interpolation. To understand these changes better, take a look at the next configuration:

  active-tenant: t2
    url: t1.example.com
    url: t2.example.com
    url: ${integrations.tenant-${integrations.active-tenant:t1}.url}/customer-service

In this case the integrations.customer-service.url configuration would be t2.example.com, since integrations.active-tenant is t2. If active tenant configuration key would not be defined, the default value (t1, defined after the :) would be used instead.

See the full changelog below.


  • Added support for configuration profiles
  • FileConfigurationSource loads additional files when configuration profile is activated


  • Improved configuration value interpolation by adding nested interpolation and default value support
  • Implemented ConfigurationSource converter functions as default interface functions
  • Upped jandex version


  • Fixed return value of yaml configuration source: return Optional.empty() if found config value is a Map or a List
  • Defined default implementation for the deprecated getConfigurationSource() method in order to be able to remove it in the next major version

Check out the release on GitHub: KumuluzEE v4.1.0

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