[Error:Java Heap Space]

Try using the following JDBC properties, to use server-side cursor. Documentation can be found in the Sun JDBC guides.

 

net.sf.jasperreports.jdbc.result.set.type

net.sf.jasperreports.jdbc.concurrency

net.sf.jasperreports.jdbc.holdability

net.sf.jasperreports.jdbc.max.field.size

[calling SP containing Temp table in IReport]

If you are usng SQL Server local temporary tables, and they are creared within the stored procedure, their lifetime is the lifetime of the stored procedure.