code: public Blob batch(String bucketName, String blobName1, String blobName2) {
      // [START batch]
      StorageBatch batch = storage.batch();
      BlobId firstBlob = BlobId.of(bucketName, blobName1);
      BlobId secondBlob = BlobId.of(bucketName, blobName2);
      batch
          .delete(firstBlob)
          .notify(
              new BatchResult.Callback<Boolean, StorageException>() {
                public void success(Boolean result) {
                  // deleted successfully
                }
  
                public void error(StorageException exception) {
                  // delete failed
                }
              });
      batch.update(BlobInfo.newBuilder(secondBlob).setContentType("text/plain").build());
      StorageBatchResult<Blob> result = batch.get(secondBlob);
      batch.submit();
      Blob blob = result.get(); // returns get result or throws StorageException
      // [END batch]
      return blob;
    }
docs: [VARIABLE "my_blob_name2"]