I am having the same problem, but all the answers I find suggest setting the default in iReport; this really isn't suitable. I have reports that run queries over multiple database schemata and am trying to parameterise the database usernames. I can do this succesfuly in iReport and set the defaults in there, and indeed the defaults work fine in jasper server. But I want to be able to override these values in jasper server, I can not guarantee the database usernames accross multiple deployments, but once deployed they are clearly unlikely to change. I don't think it is unreasonable to be want to set up a parameter with a default value to be used by a report in jasper server itself, so that the value can be updated by an end user without being prompted for that value everytime the report is run. Surely, there is no real advantage to setting a default value in the jrxml, I'd be as well hard coding the value if it can't be changed without rewriting the jrxml file anyway.
