AWS credentials provider chain that looks for credentials in this order:
- Environment Variables — AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY (RECOMMENDED since they are recognized by all the AWS SDKs and CLI except for .NET), or AWS_ACCESS_KEY and AWS_SECRET_KEY (only recognized by Java SDK)
- Java System Properties — aws.accessKeyId and aws.secretKey
- Credential profiles file at the default location (~/.aws/credentials) shared by all AWS SDKs and the AWS CLI
- Instance profile credentials delivered through the Amazon EC2 metadata service
More general docs here: http://docs.aws.amazon.com/AWSSdkDocsJava/latest/DeveloperGuide/credentials.html
