It's not useful. Again, I must reiterate: the kjava classes that come with the CLDC reference implementation are unsupported and incomplete and shouldn't be used for any serious development.
You should either roll your own stuff using the low-level graphics calls, use a library that does just that (kAWT being the best example), or else wait for the MIDP and PDAP implementations to show up on the Palm.
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Eric Giguere
author of:
Java 2 Micro Edition : A Professional Developer's Guide
PalmTM Database Programming: The Complete Developer's Guide