Using JasperReports 6.20.0 (also tried .3), I initially ran into issues with negative numbers being rendered without the leading hyphen (using pattern "###0.0")
Adding a bit of context so that others may be able to find this:
I thought I was only seeing this in production (Docker, jetty:10-jre11 based), not locally in Studio. After a few hours I understood it was also happening locally, but only if I saved the output to PDF.
I think the real issue is the usage of long hyphen (em-dash), because when I inserted the same character into a static text field it disappeared in the PDF output.
If I switch font to Dejavu Sans, it renders correctly. The file says "SansSerif", but pdffonts tells me Helvetica is being used in the output.
I am using Norwegian as my locale, in production that is
java.util.Locale locale = new Locale( "no", "NO" );
Where can I modify the locale to use a regular dash, or what other options to I have? I much prefer Helvetica to Dejavu Sans
I have temporarily set the pattern to #0.0##;(-#0.0##) , which still renders without the - , but at least with the parentheses.