code: @Override
      protected void initializeImpl()
      {
          //initialize
          super.initializeImpl();
          
          //initialize templates
          this.initializeMailTemplates();
  
          //get logger
          Logger logger=this.getLogger();
  
          //validate mail address template
          if(this.mailAddressTemplate==null)
          {
              throw new FaxException("Mail address template not defined in fax4j.properties. Property: "+FaxClientSpiConfigurationConstants.MAIL_ADDRESS_TEMPLATE_PROPERTY_KEY);
          }
          logger.logDebug(new Object[]{"Using mail address template: ",this.mailAddressTemplate},null);
          
          //validate mail subject template
          if(this.mailSubjectTemplate==null)
          {
              throw new FaxException("Mail subject template not defined in fax4j.properties. Property: "+FaxClientSpiConfigurationConstants.MAIL_SUBJECT_TEMPLATE_PROPERTY_KEY);
          }
          logger.logDebug(new Object[]{"Using mail subject template: ",this.mailSubjectTemplate},null);
      }
docs: This function initializes the fax client SPI.