code: public static String discoverCertDirLocation() {
          String location = null;
  
          location = getDir(globus_dir + "certificates");
          if (location != null) return location;
  
          if (getOS() == UNIX_OS) {
              location = getDir( "/etc/grid-security/certificates");
              if (location != null) return location;
          }
  
          String suffix = File.separator + "share" + File.separator +
              "certificates";
  
          location = getDir(System.getProperty("GLOBUS_LOCATION") +
                            suffix);
          if (location != null) return location;
  
          return null;
      }
docs: Discovers location of CA certificates directory.
  First the ${user.home}/.globus/certificates directory is checked.
  If the directory does not exist, and on a Unix machine, the
  /etc/grid-security/certificates directory is checked next.
  If that directory does not exist and GLOBUS_LOCATION
  system property is set then the ${GLOBUS_LOCATION}/share/certificates
  directory is checked. Otherwise, null is returned.
  This indicates that the certificates directory could
  not be found.