https://github.com/avaje/avaje-config
Application configuration / properties loading for JVM applications
https://github.com/avaje/avaje-config
application-configuration avaje dynamic-configuration java jvm kotlin properties properties-loader yaml
Last synced: 10 days ago
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Application configuration / properties loading for JVM applications
- Host: GitHub
- URL: https://github.com/avaje/avaje-config
- Owner: avaje
- License: apache-2.0
- Created: 2018-12-05T23:58:04.000Z (over 7 years ago)
- Default Branch: main
- Last Pushed: 2026-05-29T05:13:19.000Z (23 days ago)
- Last Synced: 2026-05-29T07:15:35.939Z (23 days ago)
- Topics: application-configuration, avaje, dynamic-configuration, java, jvm, kotlin, properties, properties-loader, yaml
- Language: Java
- Homepage: https://avaje.io/config
- Size: 719 KB
- Stars: 100
- Watchers: 2
- Forks: 11
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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# [Avaje Config](https://avaje.io/config/)
This library loads properties files that can be used to configure
an application including "testing" and "local development" and
dynamic configuration (changes to configuration properties at runtime).
```xml
io.avaje
avaje-config
${avaje.config.version}
```
## Typical use
- Put application.yaml into src/main/resources for properties that have reasonable defaults
- Put application-test.yaml into src/test/resources for properties used when running tests
- Specify external properties via command line arguments. These effectively override application.yaml properties.
## Config use
Getting property values
```java
// get a String property
String value = Config.get("myapp.foo");
// with a default value
String value = Config.get("myapp.foo", "withDefaultValue");
// also int, long and boolean with and without default values
int intVal = Config.getInt("bar");
long longVal = Config.getLong("bar");
boolean booleanVal = Config.getBool("bar");
```
Register callback on property change.
```java
Config.onChange("myapp.foo", newValue -> {
// do something ...
});
Config.onChangeInt("myapp.foo", newIntValue -> {
// do something ...
});
Config.onChangeLong("myapp.foo", newLongValue -> {
// do something ...
});
Config.onChangeBool("myapp.foo", newBooleanValue -> {
// do something ...
});
```
## Loading properties
Config loads properties from expected locations as well as via command line arguments.
Below is the how it looks for configuration properties.
- loads from main resources (if they exist)
- application.yaml
- application.properties
- loads files from the current working directory (if they exist)
- application.yaml
- application.properties
- loads via system property `props.file` or environment variable `PROPS_FILE` (if defined)
- loads via system property `avaje.profiles` or environment variable `AVAJE_PROFILES` (if defined).
Setting the `config.profiles` or environment variable `CONFIG_PROFILES` will cause avaje config to load the property files in the form `application-${profile}.properties` (will also work for yml/yaml files).
For example, if you set the `config.profiles` to `dev,docker` it will attempt to load `application-dev.properties` and `application-docker.properties`.
- loads via `load.properties` property.
We can define a `load.properties` property which has name of property file in resource folder, or path locations for other properties/yaml files to load.
`load.properties` is pretty versatile and can even be chained. For example, in your main application properties, you can have `load.properties=application-${profile:local}.properties` to load based on another property, and in the loaded properties you can add `load.properties` there to load more properties, and so on.
Example application.properties:
```
common.property=value
load.properties=application-${profile:local}.properties,path/to/prop/application-extra2.properties
```
- loads test resources (if they exist, nb: Test resources are only visible when running tests)
- application-test.properties
- application-test.yaml
If no test resources were loaded then it additionally loads from "local dev" and command line:
- loads from "local dev".
We can specify an `app.name` property and then put a properties/yaml file at: `${user.home}/.localdev/{appName}.yaml`
We do this to set/override properties when we want to run the application locally (aka main method)
- loads from command line arguments
Command line arguments starting with `-P` can specify properties/yaml files to load
When properties are loaded they are merged/overlayed.
### config.load.systemProperties
If we set `config.load.systemProperties` to true then all the properties that have been loaded are then set into system properties.