Saurabh, Welcome to the JavaRanch! It is my understanding that ThreadGroup is not covered by the real exam. The real exam seems to emphasize the Object.wait and Object.notify methods. You can also expect to see the Thread.join method. The Thread.interrupt method might appear but its use does not seem to be emphasized.
Dan Chisholm<br />SCJP 1.4<br /> <br /><a href="http://www.danchisholm.net/" target="_blank" rel="nofollow">Try my mock exam.</a>
Howdy, just wanted a bit to Dan's post. His description of the role of interrupt() on the exam is exactly right. Since most designs do not use interrupt() as a means of thread communication, we didn't want to emphasize it on the real exam. In addition to the things already listed in this discussion, You can also expect a question or two about the key Thread constructors, the sleep() method, and the start() method. cheers, Kathy