I have list of number which I want to process in batches.
example 1: input1 = [1, 2, 3, 4, 5, 6, 7, 8, 9] //(List of number) input2 = 5 //(Batch size) output = [[1, 2, 3, 4, 5], [6, 7, 8, 9]] example 2: input1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]//(List of number) input2 = 5//(Batch size) output = [[1, 2, 3, 4, 5], [6, 7, 8, 9, 10]] Here is an example using a java stream ,
public static void main(String[] args) throws Exception { List<Integer> list = new ArrayList<>(Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)); int batchSize = 5; AtomicInteger ai = new AtomicInteger(); Collection<List<Integer>> chunkedOrders = list.stream() .collect(Collectors.groupingBy(item -> ai.getAndIncrement() / batchSize)).values(); System.out.println("Your innerlist = " + chunkedOrders); chunkedOrders.forEach(chunk -> { System.out.println("Processing" + " " + chunk.size() + " " + " data, sublist = " + chunk); }); } Output:
Your innerlist = [[1, 2, 3, 4, 5], [6, 7, 8, 9, 10], [11]] Processing 5 data, sublist = [1, 2, 3, 4, 5] Processing 5 data, sublist = [6, 7, 8, 9, 10] Processing 1 data, sublist = [11] 
public class Solution { public static <T> List<List<T>> breaks(List<T> tList, int length) { if (length <= 0) throw new IllegalArgumentException( "The chosen length is less than or equal to zero: " + length ); int size = tList.size(); if (size <= 0) return new ArrayList<>(); int fullChunks = (size - 1) / length; return IntStream.range(0, fullChunks + 1).mapToObj( n -> tList.subList(n * length, n == fullChunks ? size : (n + 1) * length) ).collect(Collectors.toList()); } public static void main(String args[]) { // Original list List<Integer> list1 = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14); // Printing of the original list System.out.println(list1); // Broken list List<List<Integer>> list2 = breaks(list1,5); // Print of the broken list System.out.println(list2); } } 