Eu dou um java -version e aparece:
java version "1.4.2"
gij (GNU libgcj) version 4.1.0 (Ubuntu 4.1.0-1ubuntu8)
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
isso indica que a instalação do Java 5 nao foi bem feita?