In the JavaDoc, it's clearly defined how to set a property in SonarQube using org.sonar.api.config.PropertyDefinition in a plugin, however there is nothing on how to get it.
It seems to not work like System.getProperty(key) in Java, so, should I declare a new class that implements Configuration? Is there a way to reach these properties back properly?
You can get a Configuration object through a Context one or by injecting it through extension point constructor:
public MyExtensionPoint(Configuration config) {
this.config = config;
}
Use context.config() to get your Configuration object.
Then use configuration.get("key") to get the property.