code: private void configureClientFactories()
      {
          ClientMetadataBuilder builder = new ClientMetadataBuilder(getProperties(), kunderaMetadata,
                  getPersistenceUnits());
          builder.buildClientFactoryMetadata(clientFactories, kunderaMetadata);
      }
docs: Initialize and load clientFactory for all persistenceUnit with external
  properties.
  
  @param persistenceUnit
  @param externalProperties