By all means go for the Java 2 Certification if those are your only concerns! Don't use up energy to pass an old exam. The Java 2 exam has been out for at least one year now.
GridBagLayout should be in the Java 1.1 also! On Collections all you have to learn is the most basic of things. What are the main differences between List, Map and Set. Add "ordered" to that and that's it.
I hope I caught you on time!