The DATABASE_PROPERTIES_FILE configuration option is not in Flux 7+.

You can either place your properties directly into your Flux engine configuration, or create your engine programatically and import your database properties.

For instance:

public static void main(String[] args) throws IOException, EngineException {
FileInputStream fis = new FileInputStream(newFile("/temp/file.properties"));
Properties props = new Properties();
     try {
     props.load(fis);
     } finally {
     fis.close();
}
 
Factory factory = Factory.makeInstance();
Configuration config = factory.makeConfiguration();
config.setDatabaseProperties(props);
}