Airline GST Invoice Web Scraping

I'm looking for a web scraping script that can download airline GST invoices from provided URLs. The input data consists of up to 100 rows of airline PNRs and emails. The script should ideally be written in Java, and it needs to download all invoices in PDF format into a single ZIP file. The URLs for these invoices are publicly accessible, so no authentication is required.

Key Requirements:
- Java programming skills
- Experience with web scraping
- Ability to handle downloading and zipping of files
- Knowledge of PDF file handling

Please let me know if you can assist with this project.