Why does (i

• i <= j is evaluated to true, because auto unboxing happens for int
  comparisons and then both i and j hold the default value, 0.

• j <= i is evaluated to true because of the above reason.

• i != j is evaluated to true, because both i and j are
  different objects. And while comparing objects, there isn’t any need of
  auto unboxing.

All the conditions are true, and you are not changing i and j in loop, so it is running infinitely.