Is my Amazon S3 client synchronous or asynch?

This statement, from the documentation is pointing to a synchronous operation. Moreover it doesnt take any parameter for asynch indication of the result.

"Amazon S3 never stores partial objects; if during this call an exception wasn't thrown, the entire object was stored." http://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/services/s3/AmazonS3Client.html#putObject(com.amazonaws.services.s3.model.PutObjectRequest)