Line in Detail band causes extra space in ireport

[Thj s]

I'm getting extra space between each rows.
I've done the following.
  1.The page heading is placed in Page Header.
  2.In summary band, placed  the details of the report.
  3.The results in the summary band repeats according to the data.
If I've placed vertical lines to separate each columns in the summary band, extra space appears (vertical line is not touching the horizontal line ) while opening the report.