Earlier quoted context omitted.
Can you elaborate on this? Integer a = new Integer(2); Integer b = a; Here a == b and no comparison by value. Integer c = new Integer(2); Then a != c but a.equals(c) (in Java). My point is that I do not agree with that and would like to have a == c, which would be the case if '==' was implemented using comparison by value.
> Here a == b and no comparison by value. Um, nonsense? class Intbox { public static void main(String[] args) { Integer a = new Integer(2); Integer b = a; System.out.println(a == b); System.out.println(a.equals(b)); } } $ java Intbox true true
I believe what your parent is emphasizing the difference between comparing a == c and a == b. Both are identity comparisons as opposed to value comparisons.
> cat intbox.java
class Intbox {
public static void main(String[] args) {
Integer a = new Integer(2);
Integer b = a;
Integer c = new Integer(2);
System.out.printf("a == b => %b\n", a == b);
System.out.printf("a.equals(b) => %b\n", a.equals(b));
System.out.printf("a == c => %b\n", a == c);
System.out.printf("a.equals(c) => %b\n", a.equals(c));
}
}
> javac intbox.java
> java Intbox
a == b => true
a.equals(b) => true
a == c => false
a.equals(c) => true
That's separate from the decision Java made that == was for identity comparison. Some people disagree with that decision.