Properties

Open a report in JReport Designer. In the Report Inspector, select the node that represents the report tab and you will find the three Exit function properties: After Init Parameter, After Run and Before Run.

After Init Parameter
When running the report, after you enter parameters in the parameter dialog, this function allows you to call a program developed by yourself.
After Run
Allows you to call a program developed by yourself after running a report.
Before Run
Calls a program developed by yourself just before running a report.

Reference: For API information, see JReport Javadoc jet.util package and jet.exception package in <install_root>\help\api.