I developed my program on Windows XP. The font was set to 12 point for most fields. The size was readable and adequate. When I tried running on Windows 7, the font size on screen is tiny. A 12 size font now appears like it is size 6! However, this is not uniform. Text that is set on some widgets - like on Table column headers and Choice boxes, appear large - 12 point size font like before. But now on the scaled down gui widgets, they are cut off. The display resolution is defaulted to 1920 x 1080. Here is a screenshot below. For instance, here is the stock JavaFX tutorial sample for table running on Windows 7. It was modified to specify the font size. Notice how tiny the font size 12 is on Win7. Also see that the table column header font is much larger and overflows:
http://stackoverflow.com/questions/18495823/javafx-text-fonts-are-tiny-on-windows-7

I removed specifying font sizes and now the font size is readable - however, this means one cannot specify any font size at all - which is equally bad! However when I open it in screenbuilder 1.1, the unspecified font size is set to size 15 which will be enormous on XP!