code: private static String stripHostname(final String originalHostname) {
  
  		// Check if the hostname domains the domain separator character
  		final int index = originalHostname.indexOf(DOMAIN_SEPARATOR);
  		if (index == -1) {
  			return originalHostname;
  		}
  
  		// Make sure we are not stripping an IPv4 address
  		final Matcher matcher = IPV4_PATTERN.matcher(originalHostname);
  		if (matcher.matches()) {
  			return originalHostname;
  		}
  
  		if (index == 0) {
  			throw new IllegalStateException("Hostname " + originalHostname + " starts with a " + DOMAIN_SEPARATOR);
  		}
  
  		return originalHostname.substring(0, index);
  	}
docs: Looks for a domain suffix in a FQDN and strips it if present.
  
  @param originalHostname
  the original hostname, possibly an FQDN
  @return the stripped hostname without the domain suffix