is a comprehensive, open-source Java application designed to perform a vast range of modifications on PDF documents. Often described as the "Swiss Army Knife" for PDFs, it allows users to combine, split, rotate, and watermark files, among many other advanced "tweaks". Core Features and Capabilities

You can download several versions from the official SourceForge page :

Add watermarks for branding or security, and include page transition effects for presentations. How to Download and Install jPDF Tweak

jPDF Tweak Download: The Ultimate Swiss Army Knife for PDF Files

Create printable booklets, reverse page orders, or display multiple pages on a single sheet (n-up printing).