split a list into sublists by grouping **only** repeated elements that are adjacent to each other

Is there a simple way to split a list into sublists by grouping only repeated elements that are adjacent to each other?

Simple example with the folowing list of strings:

Input:  [RED,RED,BLUE,BLUE,BLUE,GREEN,BLUE,BLUE,RED,RED]

Output:  [[RED,RED],[BLUE,BLUE,BLUE],[GREEN],[BLUE,BLUE],[RED,RED]]

If I use groupingBy from java streams all elements which are equal will end up in the same sublist, which I want to avoid. Any ideas?

You can create a custom collector:

List<String> input = Arrays.asList("RED", "RED", "BLUE", "BLUE", "BLUE", "BLUE", "RED", "RED");
List<List<String>> output = input.stream()
        .collect(Collector.of(ArrayList::new, (accumulator, item) ->
        {
            if(accumulator.isEmpty())
            {
                List<String> list = new ArrayList<>();
                list.add(item);
                accumulator.add(list);
            }
            else
            {
                List<String> last = accumulator.get(accumulator.size() - 1);
                if(last.isEmpty() || last.get(0).equals(item)) last.add(item);
                else
                {
                    List<String> list = new ArrayList<>();
                    list.add(item);
                    accumulator.add(list);
                }
            }
        }, (left, right) -> {left.addAll(right); return left;}));