The ucar.util.prefs package is an extension of the jdk1.4 package java.util.prefs. It adds these features:

1. it always uses XML files to store preference values
2. it allows chains of “stored defaults”
3. it allows storage of arbitrary objects using Java Bean persistence (jdk1.4 )

See http://www.unidata.ucar.edu/staff/caron/prefs/