Set the JPanel size to fill parent with little margin

Question

I have two Jpanel (JpanelLeft and JpanelLeftContent) how can i make the JpanelLeftContent fill parent size with a little margin on the lef

Answer 1

Take a look at how Borders work. Especially
BorderFactory.createEmptyBorder(int top, int left, int bottom, int right) might be helpfull.