AmazonS3: Getting warning: S3AbortableInputStream:Not all bytes were read from the S3ObjectInputStream, aborting HTTP connection

Got the answer via other medium. Sharing it here:

The warning indicates that you called close() without reading the whole file. This is problematic because S3 is still trying to send the data and you're leaving the connection in a sad state.

There's two options here:

1. Read the rest of the data from the input stream so the connection can be reused.
2. Call s3ObjectInputStream.abort() to close the connection without reading the data. The connection won't be reused, so you take some performance hit with the next request to re-create the connection. This may be worth it if it's going to take a long time to read the rest of the file.

To add an example to Chirag Sejpal's answer (elaborating on option #1), the following can be used to read the rest of the data from the input stream before closing it:

S3Object s3object = s3Client.getObject(new GetObjectRequest(bucket, key));

try (S3ObjectInputStream s3ObjectInputStream = s3object.getObjectContent()) {
  try {
    // Read from stream as necessary
  } catch (Exception e) {
    // Handle exceptions as necessary
  } finally {
    while (s3ObjectInputStream != null && s3ObjectInputStream.read() != -1) {
      // Read the rest of the stream
    }
  }

  // The stream will be closed automatically by the try-with-resources statement
}

I ran into the same problem and the following class helped me

@Data
@AllArgsConstructor
public class S3ObjectClosable implements Closeable {
    private final S3Object s3Object;

    @Override
    public void close() throws IOException {
        s3Object.getObjectContent().abort();
        s3Object.close();
    }
}

and now you can use without warning

try (final var s3ObjectClosable = new S3ObjectClosable(s3Client.getObject(bucket, key))) {

//same code

}