FULL PRODUCT VERSION :


ADDITIONAL OS VERSION INFORMATION :
64-bit Ubuntu 14.04

A DESCRIPTION OF THE PROBLEM :
The current implementation of the "hashCode" function in the convenience class "Pair" is as follows.

    public int hashCode() {
        // name's hashCode is multiplied by an arbitrary prime number (13)
        // in order to make sure there is a difference in the hashCode between
        // these two parameters:
        // name: a value: aa
        // name: aa value: a
        return key.hashCode() * 13 + (value == null ? 0 : value.hashCode());
    }

However, this is an incorrect way to compute a hash code of two values. For example, here is a trivial collision of two hash codes which should be different.

    System.out.println(
        new Pair<Integer,Integer>(1,0).hashCode()
            ==
        new Pair<Integer,Integer>(0,13).hashCode()
    ); // => true

This can lead to hard-to-find bugs anywhere that instances of Pair are used in a data structure like a HashSet or HashTable.


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javafx.util.Pair;
public class Solution {
    public static void main(String args[] ) throws Exception {
        System.out.println(
            new Pair<Integer,Integer>(1,0).hashCode()
                ==
            new Pair<Integer,Integer>(0,13).hashCode());
    }
}
---------- END SOURCE ----------