Why should I place a loop inside the try-catch block when using Thread.sleep(..) ?

Liang mentioned in his book, Introduction to Java Programming(2009), that when we use Thread.sleep(..) in side the loop, the entire loop has to be wrapped with try-catch block rather than just loop only. Please anyone can explain this ? I have no idea what the heck it does mean.

Please go see his book from:
http://books.google.com/books?id=juuPxtSCg50C&pg=PA935&lpg=PA935&dq=%22If+the+loop+is+outside+the+try-catch+block+%22&source=bl&ots=TxU4lm8Wx1&sig=rzr8ziwK0qejzbtFhi0RRK31JyY&hl=en&ei=6dAXTeyjBcSAlAfO9fDHBQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBMQ6AEwAA