docs: protected SparkApplication[] getApplications(final FilterConfig filterConfig) throws ServletException {
  
          String applications = filterConfig.getInitParameter(APPLICATION_CLASS_PARAM);
          SparkApplication[] solvedApplications = null;
  
          if (StringUtils.isNotBlank(applications)) {
              final String[] sparkApplications = applications.split(",");
  
              if (sparkApplications != null && sparkApplications.length > 0) {
                  solvedApplications = new SparkApplication[sparkApplications.length];
  
                  for (int index = 0; index < sparkApplications.length; index++) {
                      solvedApplications[index] = getApplication(sparkApplications[index].trim());
                  }
              } else {
                  throw new ServletException("There are no Spark applications configured in the filter.");
              }
          }
  
          return solvedApplications;
      }