@Override
public int hashCode ()

Overriding: java.lang.Object

Returns a hash code for this Double object. The result is the exclusive OR of the two halves of the long integer bit representation, exactly as produced by the method doubleToLongBits(double), of the primitive double value represented by this Double object. That is, the hash code is the value of the expression:

(int)(v^(v>>>32))
where v is defined by:
long v = Double.doubleToLongBits(this.doubleValue());

Returns:  a hash code value for this object.