txt file upload and download to google cloud in java

Can anyone please tell me the simplest way to upload and download .txt files to google cloud storage in android using buckets. i have done it for aws using transfer utility but found not enough help for google cloud.
i have googled and found this
InputStream content = new ByteArrayInputStream(“Hello, World!”.getBytes(UTF_8));
Blob blob = bucket.create(blobName, content, “text/plain”);
how to use this to upload text file?