PDF Studio Viewer is a cross-platform PDF reader that is reliable and
easy to use. PDF Studio Viewer can annotate PDF documents and fill
interactive forms. For more editing features, there is the pdfstudio
package.

PDF Studio Viewer is a free proprietary Java based program (while
pdfstudio is not free).

Key features of PDF Studio Viewer:

 * Display PDFs with high fidelity
 * Annotate & Markup PDFs
 * Fill & Save Forms
 * Render Digital Signatures & Layers
 * Advanced User Interface
 * Advanced Print & Search Options
 * Document Storage Integrations
 * DocuSign Integration

Java comes bundled with the PDF Studio Viewer.
