manuatilomb

Solved. The problem was in the customizer class. Here's the final result:
public void customize(JFreeChart chart, JRChart jasperChart) { XYItemRenderer areaRender=new XYAreaRenderer(); XYPlot plot=chart.getXYPlot(); XYDataset dataset=plot.getDataset(); plot.setDataset(1, dataset); plot.mapDatasetToRangeAxis(1,0); plot.setRenderer(1, areaRender); XYItemRenderer lineRender=plot.getRenderer(0); lineRender.setSeriesPaint(0, new Color(0,0,255)); lineRender.setSeriesPaint(1, new Color(0,255,0)); lineRender.setSeriesPaint(2, new Color(255,0,0)); areaRender.setBaseSeriesVisibleInLegend(false); areaRender.setSeriesPaint(0, new Color(0f,0f,1.0f,0.2f)); areaRender.setSeriesPaint(1, new Color(0f,1.0f,0f,0.2f)); areaRender.setSeriesPaint(2, new Color(1.0f,0f,0f,0.2f)); }[/code]

Welp, seems like I was right. It was a type difference. I just made a test and proved it. If a textfield uses a date, it will format the spanish month name in lowercase, and if it is a text, it will format the first letter in uppercase.
EDIT
Found out that my previous answer was wrong. The text field was showing uppercase, but only because it wasn't using the report locale, so the language parsing to was the default one (english). Once the spanish locale was set on the SimpleDateFormat, it parsed it in spanish and lowercase, like before. After searching a bit, it turns out that the lowercase is the default aspect of spanish months in java, so this isn't a ireport or jasper issue whatsoever

Nevermind. I located the problem... I was trying to set dinamic text... on a static label... It's working fine with textboxes...