The first thing which came into my mind was iText. It's well know Java library with good reputation. But... there is some stopper. iText version 5+ is released under the AGPL license. I.e. we have to pay money if we want to use iText in commercial product.
I've created the next small checklist which covers project needs:
- liberal license
- support maximum amount of project features (e.g. absolute element positioning)
- good documentation
- huge amount of samples
- possibility to render HTML to PDF
- iText 5.0+ AGPL license
- iText 4.2 MPL/LGPL licenses
- PDF Box Apache License, Version 2.0
- JPedal JPedal has a LGPL release to provide a full java PDF viewer under a LGPL license
- FOP Apache License, Version 2.0
- gnujpdf LGPL License
- PJX GPLv2 License
- PDFjet Strange Open Source license model
- jPod BSD License
- PDF Renderer Maintaining is not active
- iText 2.1.7: the latest official release under the MPL & LGPL license;
- iText 4.2.0: the latest unofficial release under the MPL & LGPL license;
- iText 5.0.0 and higher: released under the AGPL license.
Beginning with iText version 5.0 the developers have moved to the AGPL to improve their ability to sell commercial licenses. .. To assist those desiring to stick with the old license was made the final MPL/LGPL version more easily available and forked on github.
Apache™ FOP (Formatting Objects Processor) is a print formatter driven by XSL formatting objects (XSL-FO) and an output independent formatter. It is a Java application that reads a formatting object (FO) tree and renders the resulting pages to a specified output. This lib doesn't have enough flexibility for absolute page element positioning. But, it might be really valuable as content convertor.
Apache PDFBoxVery interesting project. It has very impressive amount of features. And most important it's in active development.
SummaryI've selected iText v.4.2 which has acceptable license and huge community. But the most important feature it's a very good documentation (actually it's a book iText in Action — 2nd Edition), tons of samples. Almost all samples for iText v.5 can be easily applied to iText v.4.2.
Other libraries have not so much samples/demos. And for quick start it's very important.
Here is maven dependency info:
PDFBox is selected as backup library. I.e. I will use it when iText has some limitations.
com.lowagie itext 4.2.0