There is system, that has data, and can provide it\'s data with web-services (for example Lotus Notes database). Can Jasper get data for it\'s report by calling web-service?
You can write a custom DataSource by implementing the interface JRDataSource.
Full explanation: http://jasperforge.org/uploads/publish/jasperreportswebsite/trunk/sample.reference/datasource/index.html#customdatasource.