List<BoxItem> products = new ArrayList<>();

products.add(new BoxItem(Box.newBuilder().withId("Shoes").withSize(6, 10, 2).withRotate3D().withWeight(25).build(), 1));
products.add(new BoxItem(Box.newBuilder().withId("Pants").withSize(4, 10, 1).withRotate3D().withWeight(25).build(), 1));
products.add(new BoxItem(Box.newBuilder().withId("Hat").withSize(4, 10, 2).withRotate3D().withWeight(50).build(), 1));

// add a single container type
Container container = Container.newBuilder()
    .withDescription("1")
    .withSize(10, 10, 3)
    .withEmptyWeight(1)
    .withMaxLoadWeight(100)
    .build();
    
// with unlimited number of containers available
List<ContainerItem> containerItems = ContainerItem
    .newListBuilder()
    .withContainer(container)
    .build();