During February 2026, Son Thien developed a new PDF file upload endpoint for the EntryResource in the JabRef/jabref repository. This feature enables users to manage linked files within the database by supporting PDF uploads, with files automatically renamed according to a suggested pattern. Son Thien implemented robust error handling to address missing entries or directories, which reduces upload failures and enhances data integrity. The work focused on backend development and REST API design using Java, with careful attention to file handling. While the contribution was limited to a single feature, it addressed a clear need and improved document attachment reliability.