Welcome with a very nice book title "Java Interview Guide".
I am working as QA engineer since last 5 years now and have exp writing test scripts using core Java. I am planning to move to Java development roles soon and currently preparing for it. How helpful this book will be for a non-developer/QA person to prepare for Java development role interviews?
Congrats on moving from QA to development! I have seen both sides and I must say, programming is more fun.
I think that you should start out with a book thats more geared towards java basics and object-oriented concepts. I recommended the Head First Java books in another question as a great beginner book. Without reading something like that, I would fear that my book is too succinct for a non-developer to benefit from on its own. However, I do believe it is a great compliment to a beginner book, because it removes a lot of the fluff and helps people focus on what topics are important for an interview.
I hope this helps, and good luck with your transition!