I\'m working on a system that includes a large number of reports, generated using JasperReports. One of the newer features is that you can define styles for reports.
Use JasperReport templates. A JasperReports template is one that ends in .jrtx, and may look similar to this (styles.jrtx):
and then in your .jrxml file, include it as a template:
...
...
iReport also understands this, so your styles are imported and shown in iReport correctly (though I did notice sometimes it wouldn't pick them up an a reload or recompile was necessary).