private String initiateMultipartUpload(CopyObjectRequest origReq) {

        EncryptedInitiateMultipartUploadRequest req = new EncryptedInitiateMultipartUploadRequest(
                origReq.getDestinationBucketName(),
                origReq.getDestinationKey()).withCannedACL(
                origReq.getCannedAccessControlList())
                .withRequesterPays(origReq.isRequesterPays())
                .withAccessControlList(origReq.getAccessControlList())
                .withStorageClass(origReq.getStorageClass())
                .withSSECustomerKey(origReq.getDestinationSSECustomerKey())
                .withSSEAwsKeyManagementParams(origReq.getSSEAwsKeyManagementParams())
                .withGeneralProgressListener(origReq.getGeneralProgressListener())
                .withRequestMetricCollector(origReq.getRequestMetricCollector())
           ;

        req.setCreateEncryptionMaterial(false);

        ObjectMetadata newObjectMetadata = origReq.getNewObjectMetadata();
        if (newObjectMetadata == null){
            newObjectMetadata = new ObjectMetadata();
        }
        if (newObjectMetadata.getContentType() == null){
            newObjectMetadata.setContentType(metadata.getContentType());
        }

        req.setObjectMetadata(newObjectMetadata);

        populateMetadataWithEncryptionParams(metadata,newObjectMetadata);

        req.setTagging(origReq.getNewObjectTagging());

        req.withObjectLockMode(origReq.getObjectLockMode())
           .withObjectLockLegalHoldStatus(origReq.getObjectLockLegalHoldStatus())
           .withObjectLockRetainUntilDate(origReq.getObjectLockRetainUntilDate());

        req.withRequestCredentialsProvider(origReq.getRequestCredentialsProvider());

        String uploadId = s3.initiateMultipartUpload(req).getUploadId();
        log.debug("Initiated new multipart upload: " + uploadId);

        return uploadId;
    }
Initiates a multipart upload and returns the upload id
aws-java-sdk-s3/src/main/java/com/amazonaws/services/s3/transfer/internal/CopyCallable.java