Best implementation for hashCode method for a collection

Question

How do we decide on the best implementation of hashCode() method for a collection (assuming that equals method has been overridden correctly) ?

Answer 1

@about8 : there is a pretty serious bug there.

Zam obj1 = new Zam("foo", "bar", "baz");
Zam obj2 = new Zam("fo", "obar", "baz");

same hashcode

you probably want something like

public int hashCode() {
    return (getFoo().hashCode() + getBar().hashCode()).toString().hashCode();

(can you get hashCode directly from int in Java these days? I think it does some autocasting.. if that's the case, skip the toString, it's ugly.)