external.configuration.area=[url | file | ${variable}]

class AbstractService{
 void initializeService() {
  ServiceUtility.injectConfigProperties(this);
 }
}

class AbstractService{
 void initializeService() {
  //do not directly call ServiceUtility, but rather use a new extension point
  //default behaviour would be same as before
  ServiceUtility.initializeService(this);
 }
}

interface IServiceInitializerFactory{
  IServiceInitializer createInstance(IService rawService);
}

interface IServiceInitializer{
 /**
  * @return the run order of the initializer, the default ininitalizer has order 0
  */ 
 double getRunOrder();

 /**
  * @return one of then ServiceInitializerResult enums.
  * ServiceInitializerResult.CONINUE lets the following initializer do their job
  * ServiceInitializerResult.STOP breaks up and ignores the following initializers.
  */ 
 ServiceInitializerResult initializeService(IService service);
}

class DefaultServiceInitializer{
 double getRunOrder(){
  return 0;
 }

 ServiceInitializerResult initializeService(IService service){
  ServiceUtility.injectConfigProperties(service);
  return ServiceInitializerResult.CONINUE;
 }
}