Even though Khalid Mughal's A Programmer's Guide to Java Certification is a good book, I would hardly recommend it to anybody studying for SCJP 1.4. The level of difficulty is very high in the abovementioned book and surpasses the actual level of difficulty of SCJP 1.4. It normally takes you a longer time to prepare for SCJP 1.4 using Khalid Mughal's book but is an excellent resource for the mastery of the basics of Java Programming language. The exercises at the end of each chapter are excellent examples to reinforce your concepts.
But I would suggest you to take a look into
Sun Certified Programmer & Developer for Java 2 Study Guide (Exam 310-035 & 310-027) by Kathy Sierra and Bert Bates . As far as it goes for me, "This is the book".
Both these books have been reviewed and you can find the reviews at the following URL:
http://www.javaranch.com/bunkhouse/Certification.jsp The simulator by Whizlabs is also quite good. I belive you are on the right track for SCJP 1.4 and all the best with your preparation.
