code: @Override
      protected void initializeImpl()
      {
          //get port name
          this.portName=this.getConfigurationValue(FaxClientSpiConfigurationConstants.PORT_NAME_PROPERTY_KEY);
          if(this.portName==null)
          {
              throw new FaxException("Port name not defined in fax4j.properties. Property: "+FaxClientSpiConfigurationConstants.PORT_NAME_PROPERTY_KEY);
          }
  
          //get fax class
          this.faxClass=Integer.parseInt(this.getConfigurationValue(FaxClientSpiConfigurationConstants.FAX_CLASS_PROPERTY_KEY));
      }
docs: This function initializes the fax client SPI.