Not working report parameter change using contributeParameters

[andrey.esaulov]

I want to form a query string through a Java extension and pass it to the JapserReports parameter before generating report.

I found a similar example (https://community.jaspersoft.com/wiki/parameter-contributors) and connected it as Source files in my report project.

http://i.stack.imgur.com/lfmEK.png

For an experiment, I'm just trying to set a strin gvalue to the $P{GRADES_TABLE_NAME} parameter in the report with parameters.put ("GRADES_TABLE_NAME", "TEST");

But this parameter does not change when generating the Report, it is equal to NULL.

Am I doing something wrong?