You are defending against 4 (with no bidding by your side). Partner leads the 2. What is your play when dummy's 4 is played?
DUMMY
A1084
LEAD
2
YOU
J975
7. Your 7, behind the 8 (and with those other spot cards) is equivalent to the J. Playing the J would be a waste. If the 7 forces out the K and partner led from Q32, he will know you have the J97.