inStreamAssetUploadRequest.setInStreamAsset(inStreamVideoAsset);
inStreamAssetUploadRequest.setCreativeId(creativeId);
// Replace the existing asset with a newly uploaded asset.
InStreamVideoCreative inStreamVideoCreative =
creativeService.replaceInStreamAsset(assetToReplace, inStreamAssetUploadRequest);
// Display a success message.
System.out.printf("Replaced companion ad asset \"%s\" in In-Stream video creative "
+ "with ID \"%s\".%n", assetToReplace, inStreamVideoCreative.getId());
}