"This exam simulator is designed to give an idea of the type and format of questions that is likely to be encountered in the Sun Certified Java Programmers Exam. For testing purposes use a User Name of guest and a Password of password. Guest login only shows 60 of the questions. For registered access to the entire database of 420 questions see" http://www.jchq.net/homepage/certkeyflier.php
As per an earlier posting, Dan Chisholm also has some excellent freely available questions on the 1.4 objectives, and you can purchase a printed version for his questions for ease of use and layout.
There is also a JavaRanch FAQ with links to many JDK1.4 exam questions. Marcus