# customizePropertySources method

1. @override

void customizePropertySources(

1. MutablePropertySources propertySources

)
override

Called during construction to allow subclasses to register default property sources.

Override this method in your custom environment implementation to add system properties, YAML or map-based configuration sources, etc.

### Example

    @override
    void customizePropertySources(MutablePropertySources sources) {
      sources.addLast(MapPropertySource('app', {
        'env': 'production',
        'debug': 'false',
      }));
    }

## Implementation

    @override
    void customizePropertySources(MutablePropertySources propertySources) {
      propertySources.addAll(propertySources.toList());
      propertySources.addLast(SystemEnvironmentPropertySource(SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME, getSystemProperties()));
      propertySources.addLast(SystemEnvironmentPropertySource(SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME, getSystemEnvironment()));
    }