The default Combobox in Mac OS is as follows:

How can I change to following one?:

P.S. - The Combobox is created in JTable.
The default Combobox in Mac OS is as follows:

How can I change to following one?:

P.S. - The Combobox is created in JTable.
Check out the brilliant MacWidgets
Here are the key steps:
JComboBox with the appropriate L&F.DefaultCellEditorsetDefaultEditor(...)TableCellRenderer getDefaultRenderer(Class columnClass)
The default UI delegate for JComboBox on Mac OS X is com.apple.laf.AquaComboBoxUI. You can replace it with your own variation of BasicComboBoxUI. There's a related example here and a more complete example in the MacWidgets collection suggested by @Dilum.