public static String getActivationKey(String gatewayAddress, Region activationRegion) throws AmazonClientException {
        return getActivationKey(gatewayAddress, 
                activationRegion == null ?
                        null : activationRegion.getName());
    }
Sends a request to the AWS Storage Gateway server running at the
specified address, and returns the activation key for that server.

@param gatewayAddress
           The DNS name or IP address of a running AWS Storage Gateway

@param activationRegionName
           The region in which the gateway will be activated.

@return The activation key required for some API calls to AWS Storage
        Gateway.

@throws AmazonClientException
            If any problems are encountered while trying to contact the
            remote AWS Storage Gateway server.
aws-java-sdk-storagegateway/src/main/java/com/amazonaws/services/storagegateway/StorageGatewayUtils.java