Calling Mathematica from Java (Eclipse)

I have no idea about Eclipse. And you didn’t post the text of the

error or even which program complained.

I do know it is best to use math (the Mathematica binary, no front
end, the text interface for the kernel) if you can. Use mathlink <->
whatever <-> kernel <-> front-end, only if you simply cannot not do
it :)

If you use “library linkage” by talking to versionally released
mathematic libs using versionally based java libs your likely to end
up with a variety of errors for every upgrade and for many or too many
customers – your asking for it. Your asking to need to release a
product so quickly it’s out at the time of a new mm release and lasts
about as long as the mm release. Being Java with mathlink you might
do better: but not certainly. There are many changes out and about in
java , mm, and platforms these days.