I was not able to get OpenNLP parser to work. There were no samples to play with, no command line tools to run. And I don’t even want to talk about documentation. That’s because there was not any. There was an attempt at lame joke (at least that’s the only sense I can make of what.html file), but no actual documentation.
Finally, I pinged my research colleague who did get the toolkit working (thanks Scott). Turns out to be there is a whole set of model files missing from the tool’s download. They are linked to from a separate page on the original website (not even in the download).
I am downloading the models now and hopefully will be on my way. But I can certainly see why this particular toolkit is mentioned much less frequently than Stanford’s or Bikel’s.
After the fact, I have also found a mini tutorial by Daniel McLaren explaining OpenNLP components and showing some sample code and output. Looks better than what’s bundled with OpenNLP itself. Maybe Daniel and Thomas Morton (author of OpenNLP) should talk.