java把list分成几个list

public static void main(String[] args) {
        List<String> list=new ArrayList<>();
        list.add("a");list.add("a");list.add("a");list.add("a");list.add("a");list.add("a");list.add("a");list.add("a");list.add("a");
        List<List<String>> sprateList = ListUtils.partition(list,5);
        System.out.println(sprateList);
    }

public class ListUtils {

    public static <T> List<List<T>> partition(final List<T> list, final int size) {
        if (list == null) {
            throw new NullPointerException("List must not be null");
        }
        if (size <= 0) {
            throw new IllegalArgumentException("Size must be greater than 0");
        }
        return new Partition<>(list, size);
    }

    private static class Partition<T> extends AbstractList<List<T>> {
        private final List<T> list;
        private final int size;

        private Partition(final List<T> list, final int size) {
            this.list = list;
            this.size = size;
        }

        @Override
        public List<T> get(final int index) {
            final int listSize = size();
            if (index < 0) {
                throw new IndexOutOfBoundsException("Index " + index + " must not be negative");
            }
            if (index >= listSize) {
                throw new IndexOutOfBoundsException("Index " + index + " must be less than size " +
                                                    listSize);
            }
            final int start = index * size;
            final int end = Math.min(start + size, list.size());
            return list.subList(start, end);
        }

        @Override
        public int size() {
            return (int) Math.ceil((double) list.size() / (double) size);
        }

        @Override
        public boolean isEmpty() {
            return list.isEmpty();
        }
    }
}