I just started this book and want to learn Java. What editor do I use that corrects syntax etc? and what JDK do the professionals use? I take it they don't use notepad and the DOS command prompt sun JDK. or at least what are the common editors and JDK's

Many Thanks.

Good question!
You'll be delighted to find an excellent editor for Java, HTML, JavaScript, and a whole lot of other languages at

www.jedit.org

jEdit is written in the Java language, so you will be trying out a really huge Java program as you proceed in the book.
You can download it for free. As a beginner you shouldn't worry about the plugins you can choose to go with it. If you have an internet connection you can always add a plugin when you find you need some extra functionality.

If you are a beginner you should follow Ivor Horton's advice: do use the MS-DOS command prompt to compile and run your Java classes. Some professionals even prefer doing it that way, although there are developer environments like Borland's JBuilder for the big projects and extensive debugging.
At least you should LEARN to employ the Sun API. Current version is 1.4.2. You should download it with the source files and the API documentation (DOCS - you read them alongside the book). The 1.5 version will be officially released soon (then it won't be called Beta anymore).

Good luck!

P.S. Just do what Ivor tells you in the book...