Errors from the DynamoDB service seems to (also) use the key "Message" (uppercase initial letter) to communicate descriptive error messages.
Version 1.3.28 of the AWS Java SDK

This release introduces a client for AWS Direct Connect, updates the Amazon S3 client with support for Website Redirects, and updates the Amazon ElastiCache client with support for Amazon VPC.

For more information, see the full release notes:
http://aws.amazon.com/releasenotes/1443240347487597
'Version 1.3.29 of the AWS Java SDK'
Merge pull request #28 from argggh/json-error

Errors from the DynamoDB service seems to (also) use the key "Message" (...
Merge branch 'aws-sdk-java-master'

Conflicts:
	src/main/java/com/amazonaws/http/HttpMethodReleaseInputStream.java
	src/main/java/com/amazonaws/http/RepeatableInputStreamRequestEntity.java
	src/main/java/com/amazonaws/services/autoscaling/AmazonAutoScalingAsync.java
	src/main/java/com/amazonaws/services/autoscaling/AmazonAutoScalingAsyncClient.java
	src/main/java/com/amazonaws/services/cloudwatch/AmazonCloudWatchAsync.java
	src/main/java/com/amazonaws/services/cloudwatch/AmazonCloudWatchAsyncClient.java
	src/main/java/com/amazonaws/services/ec2/AmazonEC2Async.java
	src/main/java/com/amazonaws/services/ec2/AmazonEC2AsyncClient.java
	src/main/java/com/amazonaws/services/elasticbeanstalk/AWSElasticBeanstalkAsync.java
	src/main/java/com/amazonaws/services/elasticbeanstalk/AWSElasticBeanstalkAsyncClient.java
	src/main/java/com/amazonaws/services/elasticloadbalancing/AmazonElasticLoadBalancingAsync.java
	src/main/java/com/amazonaws/services/elasticloadbalancing/AmazonElasticLoadBalancingAsyncClient.java
	src/main/java/com/amazonaws/services/elasticmapreduce/AmazonElasticMapReduceAsync.java
	src/main/java/com/amazonaws/services/elasticmapreduce/AmazonElasticMapReduceAsyncClient.java
	src/main/java/com/amazonaws/services/identitymanagement/AmazonIdentityManagementAsync.java
	src/main/java/com/amazonaws/services/identitymanagement/AmazonIdentityManagementAsyncClient.java
	src/main/java/com/amazonaws/services/importexport/AmazonImportExportAsync.java
	src/main/java/com/amazonaws/services/importexport/AmazonImportExportAsyncClient.java
	src/main/java/com/amazonaws/services/rds/AmazonRDSAsync.java
	src/main/java/com/amazonaws/services/rds/AmazonRDSAsyncClient.java
	src/main/java/com/amazonaws/services/simpledb/AmazonSimpleDBAsync.java
	src/main/java/com/amazonaws/services/simpledb/AmazonSimpleDBAsyncClient.java
	src/main/java/com/amazonaws/services/simpleemail/AmazonSimpleEmailServiceAsync.java
	src/main/java/com/amazonaws/services/simpleemail/AmazonSimpleEmailServiceAsyncClient.java
	src/main/java/com/amazonaws/services/sns/AmazonSNSAsync.java
	src/main/java/com/amazonaws/services/sns/AmazonSNSAsyncClient.java
	src/main/java/com/amazonaws/services/sqs/AmazonSQSAsync.java
	src/main/java/com/amazonaws/services/sqs/AmazonSQSAsyncClient.java