@Deprecated
  public static CharMatcher invisible() {
    return Invisible.INSTANCE;
  }

  /**
   * Determines whether a character is single-width (not double-width). When in doubt, this matcher
   * errs on the side of returning {@code false} (that is, it tends to assume a character is
   * double-width).
   *
   * <p><b>Note:</b> as the reference file evolves, we will modify this matcher to keep it up to
   * date.
   *

  @Deprecated
  public static CharMatcher invisible() {
    return Invisible.INSTANCE;
  }

  /**
   * Determines whether a character is single-width (not double-width). When in doubt, this matcher
   * errs on the side of returning {@code false} (that is, it tends to assume a character is
   * double-width).
   *
   * <p><b>Note:</b> as the reference file evolves, we will modify this matcher to keep it up to
   * date.
   *

  }

  //     /**
  //      * Runs all JSR166 unit tests using junit.textui.TestRunner
  //      */
  //     public static void main(String[] args) {
  //         if (useSecurityManager) {
  //             System.err.println("Setting a permissive security manager");
  //             Policy.setPolicy(permissivePolicy());
  //             System.setSecurityManager(new SecurityManager());
  //         }

  }

  //     /**
  //      * Runs all JSR166 unit tests using junit.textui.TestRunner
  //      */
  //     public static void main(String[] args) {
  //         if (useSecurityManager) {
  //             System.err.println("Setting a permissive security manager");
  //             Policy.setPolicy(permissivePolicy());
  //             System.setSecurityManager(new SecurityManager());
  //         }

        // If logging fails, e.g. due to missing memory, at least try to log the
        // message and the cause for the failed logging.
        System.err.println(e.getMessage());
        System.err.println(errorInLogging.getMessage());
      } finally {
        runtime.exit(1);
      }
    }
  }

 * will return {@code true} for many domains which (currently) are not hosts, such as {@code "com"},
 * but given that any public suffix may become a host without warning, it is better to err on the
 * side of permissiveness and thus avoid spurious rejection of valid sites. Of course, to actually
 * determine addressability of any host, clients of this class will need to perform their own DNS
 * lookups.
 *