Glue

You want the spaces in your design to expand or shrink in proportion to the size of the frame. A fixed-sized component (by definition) is inflexible. The current size of the frame is determined using:

Dimension getSize()

Then access the height and width fields of the Dimension object. This can be awkward and is usually not needed. Another invisible component that class Box creates is a glue component. Glue is thought of as stretchy caulking between components. It keeps them separated, but expands or shrinks if needed.

To create glue use one of the following:

Box.createHorizontalGlue()
Box.createVerticalGlue()