Custom java list

To do this, you will have to override the Render for the list.

Here is a ready-made example with separators with JComboBox :

 import javax.swing.plaf.basic.*; import java.awt.event.*; import javax.swing.*; import java.awt.*; public class Test extends JFrame { public Test() { getContentPane().setLayout(new FlowLayout()); final JComboBox combobox = new JComboBox(new Object[] { "Item 1", new JSeparator(JSeparator.HORIZONTAL), "Item 2", new JSeparator(JSeparator.HORIZONTAL), "Item 3", new JSeparator(JSeparator.HORIZONTAL), "Item 4", "Item 5" } ); getContentPane().add(combobox); combobox.setRenderer(new SeparatorComboBoxRenderer()); combobox.addActionListener(new SeparatorComboBoxListener(combobox)); addWindowListener(new WindowAdapter() { @Override public void windowClosing(WindowEvent we) { System.exit(1); } }); setSize(new Dimension(200, 200)); } public static void main(String[] args) throws Exception { Test main = new Test(); main.setVisible(true); } } class SeparatorComboBoxRenderer extends BasicComboBoxRenderer implements ListCellRenderer { public SeparatorComboBoxRenderer() { super(); } @Override public Component getListCellRendererComponent( JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) { if (isSelected) { setBackground(list.getSelectionBackground()); setForeground(list.getSelectionForeground()); } else { setBackground(list.getBackground()); setForeground(list.getForeground()); } setFont(list.getFont()); if (value instanceof Icon) { setIcon((Icon)value); } if (value instanceof JSeparator) { return (Component) value; } else { setText((value == null) ? "" : value.toString()); } return this; } } class SeparatorComboBoxListener implements ActionListener { JComboBox combobox; Object oldItem; SeparatorComboBoxListener(JComboBox combobox) { this.combobox = combobox; combobox.setSelectedIndex(0); oldItem = combobox.getSelectedItem(); } @Override public void actionPerformed(ActionEvent e) { Object selectedItem = combobox.getSelectedItem(); if (selectedItem instanceof JSeparator) { combobox.setSelectedItem(oldItem); } else { oldItem = selectedItem; } } }