CareerCup

The question does not make sense if the point is to have "abc" and "ABC" mapped to different hash values. It already does that by default.

If the point was to consider "abc" and "ABC" as the same key, we would have to override the hashCode() and equal() of the type we're putting in the HashMap.
This would make more sense as an interview question.

HashMap's put() and get() methods utilize the hashCode() and equals() function. Note that 'abc' and 'ABC' are distinct separate values. As such, the hashCode(abc) and hashCode(ABC) will result in different key values.

On the other side, let's say that we have a key collision and we're trying to retrieve a case sensitive value from the resulting LinkList that is created at that bucket entry. Then the .equals(abc) and .equals(ABC) can clearly distinguish what value you are seeking.

consider the string str[]="abAcD"

and if this should be hashed to the string str[]="abacd"

then toupper(str[i])-'a' would give the same result for both of them .