:P I am new to jasper. I wonder if there is a way to change the value of a list input control by selecting some value in other list. For example in my report there are two list course and subject, which each course has 6 subjects. If I change the value of course_list from A to B, and then in list of subject was changed from the subjects of A to the subjects of B. I have tried to load the data to course_list and subject_list from database. I create a parameter to store course value and the sql query of subject_list is: select subject_name from table where course=$P{course}. But it give me exception: java.lang.Exception: 1 -java.lang.NullPointerException I think the parameter is not assigned any value at that stage. Thanks million for helping! Post edited by: ky5566, at: 2007/08/09 15:12 Post edited by: ky5566, at: 2007/08/10 10:41