Regression: "Could not calculate [Algorithm] signature" error during file upload in Docker local environments (v6.10+)

What steps does it take to reproduce the issue?
Run Dataverse in a local Docker environment using the standard docker-compose configuration.

Use any version from 6.10, 6.10.1 up to 7.x.

Create a dataset and attempt to upload a file (e.g., dorastar.png) as a dataset constituent.

Note: The issue does not occur when adding the same image as a Dataverse collection thumbnail (vignette).

When does this issue occur?
Every time a file is added to a dataset in a local Docker setup. It seems to fail during the checksum calculation (MD5/SHA) immediately after the file is written to the temporary or final storage location.

Which page(s) does it occur on?
Dataset Page (Upload)

File API

What happens?
The upload fails with: [SEVERE] Could not calculate [Algorithm] signature for the new file [filename].
The file is not attached to the dataset. Curiously, this only happens on local Docker installs; deployed environments (production/staging) do not exhibit this behavior.

To whom does it occur?
All users on local Docker development environments.

What did you expect to happen?
The checksum should be calculated successfully and the file attached, as it was in version 6.9, where the issue is non-existent.

Which version of Dataverse are you using?
Broken on: 6.10, 6.10.1, 7.x (Payara 7)

Working on: 6.9

Any related open or closed issues to this bug report?
To be determined. It may be related to changes in edu.harvard.iq.dataverse.util.FileUtil or updates in the Jakarta EE / Payara underlying libraries handling I/O streams.

Screenshots / Logs:
Plaintext
2026-04-09T15:28:28.822+0000|WARNING|Payara...|edu.harvard.iq.dataverse.util.FileUtil|...|Could not calculate MD5 signature for the new file dorastar.png
Are you thinking about creating a pull request for this issue?
No.

Contact Information:
This issue was identified by the INIST (CNRS, France) team. For further technical details or reproduction environment specifics, please contact: lucas.depret@inist.fr

Reproduce the upload failure with the standard Docker Compose setup on a version from 6.10 onward, then inspect edu.harvard.iq.dataverse.util.FileUtil and the Dataset Page/File API upload path. Compare the checksum behavior with version 6.9; done means MD5/SHA calculation succeeds and the uploaded file is attached to the dataset.