Changing the default look and feel for all my swing apps

You could set the Look And Feel by invoking UIManager.setLookAndFeel before any components are created, but that would set the Look And Feel for only that application.

If you want the default Look And Feel to be changed for all applications, create the file swing.properties (if it doesn’t exist) in the javaHomeDirectorylib directory and in which you specify the default l&f:
c:jdk1.2.2jrelibswing.properties:

# Swing properties

swing.defaultlaf=com.sun.java.swing.plaf.motif.MotifLookAndFeel