One that we looked at in the past is AeroText, but that does not look like it exists as its own project anymore. I would think that it could be written in any language since we are interested in the output (the annotated entities), although it certainly would be a plus if it had a Java API that could be interfaced with. Any level from free to purchase would be appreciated.
Just a note on the use, we will be using it as a supplemental annotator. It will not be our main source of named entities generated. So, yes, I am asking for rule-based suggestions only.