When focus is in a JList filled with text and icons, by default list items should be selected when the user types the characters of their text. This is particularly visible in JFileChooser. Ideally the behavior should conform to the Look & Feel -> first letter navigation in Windows, typing the full text of the list item on the Mac (and I propose for the Java L&F as well).

This is also an accessibility issue -> good keyboard access to lists is very important.