code: private List<String> getAdditionalJarsList() {
  
      List<String> wholeAdditionalJarsList = new ArrayList<>();
  
      List<String> jobAdditionalJars =
          getJobProps().getStringList(PIG_ADDITIONAL_JARS, null, ",");
  
      List<String> jobDefinedDefaultJars =
          getJobProps().getStringList(DEFAULT_PIG_ADDITIONAL_JARS, null, ",");
      List<String> systemDefinedDefaultJars =
          getSysProps().getStringList(DEFAULT_PIG_ADDITIONAL_JARS, null, ",");
  
      /*
        if user defines the custom default pig Jar, we only incorporate the user
        settings; otherwise, only when system configurations have it, we add the system
        additional jar settings. We don't accept both at the same time.
       */
      if (jobAdditionalJars != null) {
        wholeAdditionalJarsList.addAll(jobAdditionalJars);
      }
  
      if (jobDefinedDefaultJars != null) {
        wholeAdditionalJarsList.addAll(jobDefinedDefaultJars);
      } else if (systemDefinedDefaultJars != null) {
        wholeAdditionalJarsList.addAll(systemDefinedDefaultJars);
      }
      return wholeAdditionalJarsList;
    }
docs: Merging all additional jars first from user specified property
  and private.properties (in the jobtype property) for additionalJarProperty
  TODO kunkun-tang: A refactor is necessary here. Recommend using Java Optional to better handle
  parsing exceptions.