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writing efficient hashcode implementation

anish jain
Ranch Hand

Joined: Feb 03, 2010
Posts: 129
How to write an efficient hashcode implementation so that tha hashcodes are uniformly distributed?
Campbell Ritchie

Joined: Oct 13, 2005
Posts: 44449
There is a nice example in Effective Java by Joshua Bloch. The same technique is copied into Bruce Eckel's Thinking in Java, which you may be able to find a copy of the 3rd edition on the net (legally).
Ganesh Gowtham
Ranch Hand

Joined: Mar 30, 2005
Posts: 225


Please check apache commons lang

org.apache.commons.lang.builder.HashCodeBuilder ( to build HashCode ...)

org.apache.commons.lang.builder.EqualsBuilder ( to generate Equsl() based on fields of class )

Thanks, Ganesh Gowtham
Campbell Ritchie

Joined: Oct 13, 2005
Posts: 44449
Thank you. Those Apache Commons methods might give effective hash and equals methods, but using such tools does not help one learn the algorithm, I am afraid.
I agree. Here's the link:
subject: writing efficient hashcode implementation
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