Java Lambda, Stream and Filter

I have an array [ 1,2,3,4,5 ] and wanted to do something like this.

Create a new array where all elements below 3 will become negative and all elements above and equal to 3 will remain the same. if there is no element below 3 then it that case I have to throw an error.

So in this case new array will be [ -1, -2, 3, 4, 5].

How this can be done using lambda, filter?

This is my piece of code

AtomicInteger a = new AtomicInteger(0);

arrayList.stream()
    .map(data -> {
      if(data < 3) {a.getAndIncrement(); return -1 * data;}
      return data;
    })
    .collect(Collectors.toList());

if(a.get() == 0) {
  throw  new RuntimeException();
}

This kind of does what you require

    List<Integer> mappingResult = Stream.of(1, 2, 3, 4, 5)
                                        .map(v -> v < 3 ? -v : v)
                                        .collect(Collectors.toList());
    mappingResult.stream().filter(v -> v < 3).findAny().orElseThrow(() -> new InvalidStateException("No elements less than 3"));

Or this

    AtomicBoolean b=new AtomicBoolean();
    List<Integer> mappingResult = Stream.of(1, 2, 3, 4, 5)
                                        .map(v -> v < 3 ? -v : v)
                                        .peek(v-> {if(v<3) b.set(true);})
                                        .collect(Collectors.toList());
    if(!b.get()){
        throw new InvalidStateException("No elements less than 3");
    }

If you want negatives to still be negatives, use

.map(v -> v>0 && v < 3 ? -v : v)

As comment says, you can improve that even further (I assume that comments are aligned with original requirements)

    AtomicBoolean b = new AtomicBoolean();
    List<Integer> mappingResult = Stream.of(1, 2, 3, 4, 5)
                                        .map(v -> {
                                            if (v > 0 && v < 3) {
                                                b.set(true);
                                                return -v;
                                            }
                                            return v;
                                        }).collect(Collectors.toList());
    if (!b.get()) {
        throw new InvalidStateException("No elements less than 3");
    }

You should compare input and output. If they are equal, throw an exception.

List<Integer> input = List.of(1, 2, 3, 4, 5);
List<Integer> output = input.stream()
    .map(data -> data < 3 ? -data : data)
    .collect(Collectors.toList());
if (output.equals(input))
    throw new RuntimeException();