Two days ago, I took the Sun
Java 1.2 Programmer's Exam and was shocked to pass it with a score of 100%.
I consider this a bit of a fluke, because I had to guess the answers to four or five questions in the areas of IO and AWT. I had not memorized several method signatures that these questions required. Had all my guesses been wrong, my score would have been a more realistic 91% or 93%.
I had no Java experience until late May of this year, when I downloaded the Java 1.1.8 runtime system and SDK from
http://developer.apple.com/java/classic.html . (I'm running MacOS 8.6, so this is the only version that I could use.) I also downloaded a 1.1-compatible version of Swing from
http://java.sun.com/products/jfc/download.archive.html .
I spent the next few weeks going through the online tutorials at
http://java.sun.com/docs/books/tutorial/ , starting with "Your First Cup of Java" and moving through "Getting Started", "Learning the Java Language", "Essential Java Classes", "Collections", and finally a small part of "User Interfaces that Swing: A Quick Start Guide" and "Creating a GUI with JFC/Swing".
At the same time, I borrowed Ivor Horton's "Beginning Java 2" from a library, and won a copy of the Sybex "Java 2 Complete" book at a user group meeting raffle. I also downloaded Bruce Eckel's book "Thinking in Java", but didn't end up referring to it very often.
For a couple of weeks, I interrupted my studies so I could use Java to solve a couple of programming puzzles at
http://www.itasoftware.com/careers/programmers.php . Writing real programs from scratch, even small ones like these, helped me greatly.
Finally, I began taking any mock exams that I could find linked from javaranch.com , jchq.net, and javaprepare.com . A friend lent me a CD-ROM from his Syngress Java Certification book , which contained more mock exams and sample questions. Answering questions wrong, and learning why my answers were wrong, was a good way to learn some of the more obscure details of Java.
I spent a little over 10 weeks on this, from the initial download to the final exam. Of course, it helped to be unemployed while doing this.
You might want to bring earplugs to your exam. I didn't, but wish I had, because there was sufficient ambient noise (from the office outside, from the street) to be occasionally distracting.