With insets, you can add space around a component. The cell dimensions expand to accommodate this extra space. 
See e622 Creating a GridBagLayout for an example on how to use a gridbag layout with gridbag constraints. 

    GridBagConstraints gbc = new GridBagConstraints();
    
    int top = 2;
    int left = 2;
    int bottom = 2;
    int right = 2;
    gbc.insets = new Insets(top, left, bottom, right);