@Override
    public AWSCredentials getCredentials() {
        try {
            return super.getCredentials();
        } catch (AmazonClientException ace) {

        }

        LOG.debug("No credentials available; falling back to anonymous access");
        return new AnonymousAWSCredentials();
    }
Amazon Web Services credentials provider chain for Amazon S3 that looks for credentials in
the {@link DefaultAWSCredentialsProviderChain}. If the {@link DefaultAWSCredentialsProviderChain}
returns null, S3 falls back to anonymous access.
aws-java-sdk-s3/src/main/java/com/amazonaws/services/s3/S3CredentialsProviderChain.java