Recursive move files of specific type to a specific path
How about
find ~/my/path -type f -name "*(J)*.foo" -exec mv {} ~/my/path/j \;
The -0 needs to go right after the xargs.
find -type f -name "*(J)*.foo" -print0 | xargs -0 -I{} mv \{\} j/
By the way, posting an error message or other details instead of "no luck" helps diagnose problems.