Recently I have updated my PostgreSQL database from version 8 to 11 and now I have a report with a net.sf.jasperreports.engine.JRException: Unknown column name: date eror, so I went to check the report and in fact, the column name in postgres is current_date, not date; so I went to fix this error in the query, tried to generate the report again and it gives me the exact same error. Then I tried changing the name of the field in the jrxml, make the appropriate changes, save it, and tried again, but I had the exact same error.
It is like the changes that I make in the jrxml wont save, or like the document that I modify does nothing (but I have checked many times and I am changing the exact report).
This just happens with one report in particular, the others I modify update correctly and change when I modify the jrxml.
Modifying the query then clicking on "Read Fields" should update the fields in the report outline. The problem at that point is you have to fix all expressions that were using the old name to use the corrected new name. The easiest way of finding that is to go to the XML source and doing a text search.