public static String getHostNameFirst(InetSocketAddress inetSocketAddress, String defaultHostName) {
        String hostName = getHostNameFirst(inetSocketAddress);
        if (hostName == null) {
            return defaultHostName;
        }
        return hostName;
    }
Returns the hostname of the given {@link InetSocketAddress}, or the String form of the IP address
if it does not have one. Returns {@code defaultHostName} if neither can be retrieved.

<p>This <b>does not</b> trigger a reverse DNS lookup if was created using an address and the hostname
is not yet available.

@param inetSocketAddress the socket address in which to retrieve the hostname from
@param defaultHostName   the value to return if neither the hostname nor the string form of the
                         address can be found
@return  the hostname or the String representation of the address, or the {@code defaultHostName}
         if neither can be found.

@see java.net.InetSocketAddress#getHostString()
agent-module/bootstraps/bootstrap-core/src/main/java/com/navercorp/pinpoint/bootstrap/plugin/util/SocketAddressUtils.java