any lib / api for filling in the field in microsoft doc?

I got a document that need to be filled in (it was in microsoft word doc), I have no idea how to filled in / integrated with my current web apps.

is there any good java api / lib that could be used ? preferrably the free one.

here is the example of doc that need to be filled in. http://drop.io/callmeblessed开发者_运维百科/asset/debt-agremeent-certificate-doc

Apache POI - the Java API for Microsoft Documents

If Leniel's suggestion doesn't work (I would suggest trying POI first, as well), there's the OpenOffice.org java UNO API which has a different implementation. It introduces a significant runtime dependency, but if POI doesn't cut it, it's the obvious second choice.

Docmosis can do this as long as you have control of the source document and can specify placeholders etc. It's free and makes use of OpenOffice to do the format conversions. The Docmosis engine can do document manipulation (population, repetition, deletion etc). Load balancing and scalability features are paid for though.