Hi, I think this might be a bug, but I wanted to ask here to make sure before I report it as a bug (just to be certain I'm not missing something). I use iReport 5.0.0 and Jasperreports Server 5.0.0. I added my parameters in the "Link parameters" tab of the Hyperlink window and made sure to set the proper Class names. Two of those parameters have the java.util.Date Class names. After that, I tried my report on my Jasperreports Server, but got a "java.lang.ClassCastException: java.lang.String cannot be cast to java.util.Date" error. I went back to check my hyperlink parameters and they had reverted back to java.lang.String! I thought I had forgotten to set them, so I changed it again for java.util.Date. Tried again, still same error. Went back to check, they had reverted to String again! I poked around in iReport for a bit and found out the following : Class names remain to Date if I don't save my report, but get reverted to String if I save it (which causes the error on the server, since they end up being of String type). Those parameters have the Date class in my main report and the drill down report, they are not String anywhere. I thought I could maybe change it directly in the XML, but if I try to add the class in the hyperlinkParameter tag, iReport gives me this error : "Attribute 'class' is not allowed to appear in element 'hyperlinkParameter'." I've been banging my head on this one, so if anyone has any good ideas, that would be most appreciated. If required, I can post my XML. Thanks