code: public static String getTrustRootPath() {
          String path = System.getProperty("X509_CERT_DIR");
          if (path == null) {
              path = System.getProperty("user.home") + TRUSTED_CERT_PATH;
          }
          return path;
      }
docs: Returns the trusted certificates directory location where
  writeTrustRoots() will store certificates.
  It first checks the X509_CERT_DIR system property.
  If that property is not set, it uses
  ${user.home}/.globus/certificates.
  Note that, unlike CoGProperties.getCaCertLocations(),
  it does not return /etc/grid-security/certificates or
  ${GLOBUS_LOCATION}/share/certificates.