Why Java does not see that Integers are equal?

Question

Check out this article: Boxed values and equality

When comparing wrapper types such as Integers, Longs or Booleans using == or !=, you’re comparing them as references, not as values.

If two variables point at different objects, they will not == each other, even if the objects represent the same value.

Example: Comparing different Integer objects using == and !=.

Integer i = new Integer(10);
Integer j = new Integer(10);
System.out.println(i == j); // false
System.out.println(i != j); // true

The solution is to compare the values using .equals()…

Example: Compare objects using .equals(…)

Integer i = new Integer(10);
Integer j = new Integer(10);
System.out.println(i.equals(j)); // true

…or to unbox the operands explicitly.

Example: Force unboxing by casting:

Integer i = new Integer(10);
Integer j = new Integer(10);
System.out.println((int) i == (int) j); // true

References / further reading