public void upload(InputStream is, String bucketName, String key) throws IOException{
    long partSize = 5 * 1024 * 1024;

    InitiateMultipartUploadRequest request = new InitiateMultipartUploadRequest(bucketName, key);
    InitiateMultipartUploadResult result = amazonS3.initiateMultipartUpload(request);
    String row;

    List<PartETag> partETags = new ArrayList<>();

    BufferedReader br = new BufferedReader(new InputStreamReader(is));

    ByteArrayOutputStream baos = new ByteArrayOutputStream();

    while ((row = br.readLine()) != null) {
        if (baos.size() >= partSize) {
            uploadPart(baos, partETags, result.getUploadId(), key);
            baos.reset();
        } else {
            row += 'n';
            baos.write(row.getBytes(Charset.forName("UTF-8")));
        }
    }

    CompleteMultipartUploadRequest compRequest = new CompleteMultipartUploadRequest(
            bucketName,
            key,
            result.getUploadId(),
            partETags);

    amazonS3.completeMultipartUpload(compRequest);
}


private void uploadPart(ByteArrayOutputStream baos, List<PartETag> partETags, String uploadId, String key) throws IOException
{
       int partNumber = partETags.size()+1;

        log.info("Upload part: " + partNumber + " to: " + key + " with size: " + baos.size());

        InputStream inputStream = new ByteArrayInputStream(baos.toByteArray());

        UploadPartRequest uploadRequest = new UploadPartRequest()
            .withBucketName(this.outputBucket)
            .withKey(key)
            .withUploadId(uploadId)
            .withInputStream(inputStream)
            .withPartNumber(partNumber)
            .withPartSize(baos.size());

        partETags.add(s3.uploadPart(uploadRequest));
    }