In this article, I am revisiting couple of interesting question related
to internal working of HashMap in Java, mostly asked to senior Java developers,
ranging from 4 to 6 and upto 8 years of experience. I did cover lot of these questions
from HashMap, ranging from thread-safety to race conditions, in my post about internal
working of Java HashMap, but I thought to revisit two of those questions, How get method of HashMap or Hashtable works
internally in
Java and What happens if two different
keys return same hashCode, how do you return value form HashMap in that
case. These are the question, which is highly popular in investment banking
domain, and preferred choice of interviewer, while interviewing experienced
Java professional. If these questions are still being asked, it means not many are
answering them in the clarity and confidence they are looking for. This
motivates me to revisit these questions again. On a side note, in order to
understand these questions, you should have good knowledge of equals
and hashcode method as well. At least you should know that :
1) Two unequal object may return same hashcode.
2) When two objects are equal by equals(), they must
have same hashcode.
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