I've been attempting to get information listing the differences between the Core API libraries of Java 1.4.2 and Java 5. However, majority of the sites simply list the differences/enhancements in Java 5 in terms of is functionality.
I need to know the differences between the 2 Java versions as I'm planning to sit take the SCJP exam. My 2 years background in Java is on Java 1.4.2.
Also, given that I'm from a Java 1.4.2 with no prior SCJP certification, would it be recommended for me take SCJP 5 or SCJP 6?
I doubt that you need to know the differences between 1.4 and 5 for the exam. The objectives spell out which parts of the API are required knowledge; what does it matter whether they were introduced in Java 5 or before?
Compared to Java 1.4.2, there are a lot of new features in Java 5, for example generics, autoboxing, enums, static import, etc. Some of these, such as generics, can be quite complicated, so you need time to study the new features carefully. See Java SE 5 New Features (from the JDK 5 documentation) for an overview.
The difference between Java 5 and 6 is only small. In my opinion, it's better to do SCJP 6 instead of SCJP 5 - I can't think of any reason why you wouldn't want to do the newest version of SCJP.