Your very first method has a return buried in the middle of your code. That is a gigantic red flag.

Look, what you're trying to do is simple.

  getNumbers.fold(println("Failed to load numbers"))(nums => nums.foreach(println))

That's the Scala version, but I'm sure there's a Java version of the same code. This code assumes that getNumbers returns Option[List[Int]], which your compiler can guarantee. If you want something that's a little bit more readable, try this:

  getNumbers match {
    case Some(nums) => nums.foreach(println)
    case None => println("Failed to load numbers")
  }

No null check, no loops, just very simple easy-to-read bulletproof code. This code cannot generate a NPE at all, ever.