equals and hashCode

[Gregory A. Swarthout]

From Object's JavDoc:

If two objects are equal according to the equals(Object)
method, then calling the hashCode method on each of
the two objects must produce the same integer result.

It doesn't say why this must be. Does anyone know?

 

[Wendy S]

It doesn't say why this must be. Does anyone know?

Yes, but I can't explain it nearly as well as Chapter 3 of Effective Java:
http://java.sun.com/docs/books/effective/chapters.html

 

[Silvio Bierman]

From Object's JavDoc:


It doesn't say why this must be. Does anyone know?

Look at what Wendy wrote. Without this requirement using hashing in general
container classes (HashMap, HashSet) would not be feasible.