Which free Java library can I use to generate PDFs in Java?

I have a need to generate some PDF documents through Java .. Which API or library, etc, can I use to do this in the most effective way ?

EDIT: Added requirements:

I'll be using this for a commercial application, so I'd like to work with a library which is free to use for commercial applications as well ..

Secondly, my work will be like this: I have a pre-defined PDF file which has blank text fields in it. This would be my 'template file', and can be generated manually. Then, within my program, I would then take this file, put data into the text fields and generate new PDFs. And this would be done r开发者_开发技巧epeatedly.

So for the above added requirements, what would be the best library for me now ? iText does seem appealing, but it seems I would have to pay for it if I wanted to use it in a commercial app, which I'd like to avoid ..

http://itextpdf.com/download.php

Check out iText:

http://itextpdf.com/

I am using Apache PDFBox to generate PDF in java

Reference : https://pdfbox.apache.org/

iText is probably the best, but if you cannot live with their license there is also Apache PDFBox.

If you are creating your PDF templates yourself, then you might want to look at Docmosis - it lets you create templates in Word or OpenOffice with fields that you replace when you render documents. There is a free version you can distribute with your application if your document volumes are low.