code: @Override
      protected void initializeImpl()
      {
          //get logger
          Logger logger=this.getLogger();
  
          //get use persistent connection value
          this.usePersistentConnection=Boolean.parseBoolean(this.getConfigurationValue(FaxClientSpiConfigurationConstants.USE_PERSISTENT_CONNECTION_PROPERTY_KEY));
          logger.logDebug(new Object[]{"Using persistent connection: ",String.valueOf(this.usePersistentConnection)},null);
          
          //setup connection factory
          String className=this.getConfigurationValue(FaxClientSpiConfigurationConstants.CONNECTION_FACTORY_CLASS_NAME_PROPERTY_KEY);
          this.connectionFactory=this.createMailConnectionFactoryImpl(className);
          if(this.connectionFactory==null)
          {
              throw new FaxException("Mail connection factory is not available.");
          }
      }
docs: This function initializes the fax client SPI.