If you want to change and position any component in a frame as you wish then
you should not use grid lay out. Grid layout will divide the frame and it will make the component's size in a particular grid to the size of the grid.
For keeping the size and position of your components as you wish you need to do the following:
1) set the frame lay out to null by f.setLayout(null);
2) before adding a component to frame you need to mention their co-ordinates by using setBounds method. ex: addItem.setBounds(xAxis point,yAxis point,width of the componen,height of the component)
3) once you set the position and size of your components then add it to the frame
Working with setBounds initially requires some trails as you may not get the exact position in the first go you should keep on changing the values until you get to your desired position and size. Once you get some idea how it works then its easy to set the position of your components