[json data source in subreport not working in Jasper Studio]

I didn't know about the Tracker.  The bug is above though - that expression IS valid, even though it says it isn't.

[json data source in subreport not working in Jasper Studio]

I never really got the JSON data source working but I did manage to get one working with XML.  This error message is actually a bug in JasperReports because there is nothing wrong with the expression but I couldn't get them to acknowledge it or fix it.  The support on these forums leaves a bit to be desired sadly.

[Current expression not valid ((net.sf.jasperreports.engine.data.JRXmlDataSource)$P{REPORT_DATA_SOURCE}).dataSource("/Northwind/Customers")]

Trying to put the following expression in the Data Source Expression:

((net.sf.jasperreports.engine.data.JRXmlDataSource)$P{REPORT_DATA_SOURCE}).dataSource("/Northwind/Customers") 

It gives an error in the expression editor that says:

Current expression is not valid.  Please verify it!

I know that is a valid expression so why would it be getting this error?

[json data source in subreport not working in Jasper Studio]

I'm try to do a json subreport connected to the Northwind sample database and I'm reading all over that I need the following expression in the subreport DataSourceExpression:

((net.sf.jasperreports.engine.data.JsonDataSource)$P{REPORT_DATA_SOURCE}).subDataSource("Orders")

Yet, when I try to put it in the expression editor it tells me:

The current expression is not valid. Please verify it!

Any ideas what I'm doing wrong?

[java.lang.BigDecimal class doesn't exist]

By the way, to clarify, I'm talking about when you specify the JDBC DSN, put in your select * from <tablename> and then click "Read Fields" and it pulls in all the data names and classes.

[java.lang.BigDecimal class doesn't exist]

The JDBC driver I'm connecting to is defaulting numerics to "java.lang.BigDecimal".  Of course, it should be "java.math.BigDecimal". Is there any way to override this assignment without changing it each time I define a new report?