presto-base-jdbc/src/main/java/io/prestosql/plugin/jdbc/credential/CredentialProviderModule.java/CredentialProviderModule/ConfigFileBasedCredentialProviderFactory
class CredentialProviderModule:        @Inject
        public ConfigFileBasedCredentialProviderFactory(ConfigFileBasedCredentialProviderConfig config)
                throws IOException
        {
            requireNonNull(config, "config is null");
            Map<String, String> properties = loadPropertiesFrom(config.getCredentialFile());
            credentialsConfig = new ConfigurationFactory(properties).build(CredentialConfig.class);
        }