Split list into multiple lists with fixed number of elements in java 8

You can use Guava library.

List<Integer> bigList = ... List<List<Integer>> smallerLists = Lists.partition(bigList, 10);

It sounds like a problem that is better handled like a low-level Stream operation just like the ops provided by the Stream API itself. A (relative) simple solution may look like:

public static <T> Stream<List<T>> chunked(Stream<T> s, int chunkSize) {
    if(chunkSize<1) throw new IllegalArgumentException("chunkSize=="+chunkSize);
    if(chunkSize==1) return s.map(Collections::singletonList);
    Spliterator<T> src=s.spliterator();
    long size=src.estimateSize();
    if(size!=Long.MAX_VALUE) size=(size+chunkSize-1)/chunkSize;
    int ch=src.characteristics();
    ch&=Spliterator.SIZED|Spliterator.ORDERED|Spliterator.DISTINCT|Spliterator.IMMUTABLE;
    ch|=Spliterator.NONNULL;
    return StreamSupport.stream(new Spliterators.AbstractSpliterator<List<T>>(size, ch)
    {
        private List<T> current;
        @Override
        public boolean tryAdvance(Consumer<? super List<T>> action) {
            if(current==null) current=new ArrayList<>(chunkSize);
            while(current.size()<chunkSize && src.tryAdvance(current::add));
            if(!current.isEmpty()) {
                action.accept(current);
                current=null;
                return true;
            }
            return false;
        }
    }, s.isParallel());
}

Simple test:

chunked(Stream.of(1, 2, 3, 4, 5, 6, 7), 3)
  .parallel().forEachOrdered(System.out::println);

The advantage is that you do not need a full collection of all items for subsequent stream processing, e.g.

chunked(
    IntStream.range(0, 1000).mapToObj(i -> {
        System.out.println("processing item "+i);
        return i;
    }), 2).anyMatch(list->list.toString().equals("[6, 7]")));

will print:

processing item 0
processing item 1
processing item 2
processing item 3
processing item 4
processing item 5
processing item 6
processing item 7
true

rather than processing a thousand items of IntStream.range(0, 1000). This also enables using infinite source Streams:

chunked(Stream.iterate(0, i->i+1), 2).anyMatch(list->list.toString().equals("[6, 7]")));

If you are interested in a fully materialized collection rather than applying subsequent Stream operations, you may simply use the following operation:

List<Integer> list=Arrays.asList(1, 2, 3, 4, 5, 6, 7);
int listSize=list.size(), chunkSize=2;
List<List<Integer>> list2=
    IntStream.range(0, (listSize-1)/chunkSize+1)
             .mapToObj(i->list.subList(i*=chunkSize,
                                       listSize-chunkSize>=i? i+chunkSize: listSize))
             .collect(Collectors.toList());

You can create your own collector. Something like this:

class GroupingCollector<T> implements Collector<T, List<List<T>>, List<List<T>>> {
    private final int elementCountInGroup;

    public GroupingCollector(int elementCountInGroup) {
        this.elementCountInGroup = elementCountInGroup;
    }

    @Override
    public Supplier<List<List<T>>> supplier() {
        return ArrayList::new;
    }

    @Override
    public BiConsumer<List<List<T>>, T> accumulator() {
        return (lists, integer) -> {
            if (!lists.isEmpty()) {
                List<T> integers = lists.get(lists.size() - 1);
                if (integers.size() < elementCountInGroup) {
                    integers.add(integer);
                    return;
                }
            }

            List<T> list = new ArrayList<>();
            list.add(integer);
            lists.add(list);
        };
    }

    @Override
    public BinaryOperator<List<List<T>>> combiner() {
        return (lists, lists2) -> {
            List<List<T>> r = new ArrayList<>();
            r.addAll(lists);
            r.addAll(lists2);
            return r;
        };
    }

    @Override
    public Function<List<List<T>>, List<List<T>>> finisher() {
        return lists -> lists;
    }

    @Override
    public Set<Characteristics> characteristics() {
        return Collections.emptySet();
    }
}

And then you can use it in a way like this:

    List<List<Integer>> collect = Stream.of(1, 2, 3, 4, 5, 6, 7, 8, 9, 10).collect(new GroupingCollector<>(3));
    System.out.println(collect);

Will print:

[[1, 2, 3], [4, 5, 6], [7, 8, 9], [10]]