A JMP Journal file does not contain a copy of the data, unles the data table was explictly copied to the journal. And if that was the case, you could visably see the data table when one opened the journal. I am assuming the data are not visible in the Journal.
A JMP Report(.jrp), when it is being saved, asks if the data table should be embedded into the Report file. A .jrp file is actually just a .jsl file with a different extension. So if you had the .jrp file, you would be able to extract the data.
Jim