In addition, this is working on template that doesn't have subDataset. I have created 2 jrxml, with the same jrdax, and java code. The one without subdataset works well, the one with subdataset have the java issue. I also add this property to the subdataset, or try other things without success : <subDataset name="subdata" uuid="b10ad888-7807-4c0a-8777-e6d66d476e6c"> <property name="com.jaspersoft.studio.data.defaultdataadapter" value="JsonDataAdapter.jrdax"/>