A DESCRIPTION OF THE REQUEST :
The HashMap implementation short circuits the case of the same key which avoids the potentially more costly equals() comparison at the cost of an extra comparison.



JUSTIFICATION :
Faster when using common keys

ACTUAL -
Current 1.6 HashMap:

if (e.hash == hash && ((k = e.key) == key || key.equals(k)))


Current 1.6 ConcurrentHashMap:

if (e.hash == hash && key.equals(e.key))