Subscribe to SNS Topic
//subscribe to an SNS topic
SubscribeRequest subRequest = new SubscribeRequest(topicArn, "email", "name@example.com");
snsClient.subscribe(subRequest);
//get request id for SubscribeRequest from SNS metadata
System.out.println("SubscribeRequest - " + snsClient.getCachedResponseMetadata(subRequest));
System.out.println("Check your email and confirm subscription.");