FontBox and PDFBox are not competing libraries; FontBox is actually a subproject and core dependency of PDFBox.
While PDFBox handles high-level operations for entire PDF documents, FontBox is a low-level utility focused strictly on parsing and manipulating font files. Key Differences at a Glance Feature / Aspect Primary Focus Font data parsing and low-level typography. PDF generation, manipulation, and text extraction. Scope Works with standalone font files (.ttf, .otf, .pfb). Works with .pdf files. Dependency Independent of PDFBox (can be used standalone).
Relies on FontBox to handle document text and font embedding. What is FontBox?
FontBox is a specialized, open-source Java tool used to obtain low-level information from font files. It decodes font structures so that other programs can understand exactly how a font is built.
Supported Formats: It parses TrueType (TTF), OpenType (OTF), PostScript Type 1, and Compact Font Format (CFF) files.
Core Capabilities: It extracts font metadata, reads glyph shapes (outlines), maps character codes to glyphs, and handles font subsetting to shrink file sizes. What is PDFBox?
Apache PDFBox is a comprehensive, open-source Java library used to create, render, print, and split PDF documents. An Introduction to Apache PDFBox Library: Nutshell Examples