I use it to split pdfs, as far as which is concerned it is easier than pdftk.
Note that the release Release20091027 has the tools package removed. Use a previous release instead
1. Subset the first 20 pages and three copies of the last.
java tool.pdf.Split -page 1-20,last,last,last contract.pdf
2. Rearrange pages to all odd followed by all even.
java tool.pdf.Split -page odd,even for-non-duplex-copier.pdf
3. Delete page 5.
java tool.pdf.Split -page 1-4,5-end contract.pdf
4. Insert blank page after cover page.
java tool.pdf.Split -page 1,b,2-end report.pdf
5. Split page ranges into multiple PDFs by separating ranges with semicolons.
java tool.pdf.Split -page "1-12;13-20;21-end" book-with-chapters.pdf
5. Split page first 1000 pages into multiple PDFs of 100 pages each.
java tool.pdf.Split -page "1-1000/100" big.pdf
7. For double-sided printing on a non-duplex printing, split the first 11 pages into a PDF with the odd pages and another PDF with the even pages. Since there is an odd number of pages, the PDF with the even pages is given an additional blank page in order to match the number of odd pages.
java tool.pdf.Split -page 1-11 -doublesided handouts.pdf
8. Given a PDF with rearranged pages, you can conveniently recover the original order with the backmap operator to the -page option. For example, if the PDF has all the odd pages followed by all the even pages, for a page order of 1,3,5,...,2,4,6,..., then the following back maps this ordering to the original 1,2,3,4,5,6,....
java tool.pdf.Split -page odd,even,backmap odd-even.pdf
If the odd pages are in one PDF and the even in another, you can first use the Merge tool.