SpringLayout is a powerfull layout manager; but aren't layout managers supposed to automatically resize your components for you (depending on the type of screen and if you resixe the window or not)? SpringLayout doesn't seem to do this.
Some layout managers will automatically resize the components you hand them, eg, BorderLayout and GridLayout. Some will allow the components to remain at their preferred size, eg, FlowLayout and GridBagLayout. Some layout managers will show components somewhere in the spectrum of minimum size, preferred size and maximum size according to how you put things together, eg, BoxLayout and SpringLayout. See the page Using Layout Managers in the Swing tutorial.