How to add objects to list without having array brackets

Question

I have a for loop in which I add some attributes to the object and at the end I need to have a string (to pass it as a query parameter)

I need

{"items":[{"itemsCode":"item1","isAvailable":false}],"isActive":false},{"items":[{"entryCode":"item2","isSelected":true}],"isActive":false}

When I try

List<List> itemsList= new ArrayList<>();
itemsList.add(new Items(items, isBoolean));
ObjectMapper mapper = new ObjectMapper();
String itemsJson = mapper.writeValueAsString(itemsList);

POJO

public class Items {

    private List<Item> items;
    private Boolean isBoolean;

I get this:

[{"items":[{"itemsCode":"item1","isAvailable":false}],"isActive":false},{"items":[{"entryCode":"item2","isSelected":true}],"isActive":false}]

please help how to get rid of an array brackets, but keeping the convention of adding those object to a list in a for loop

Answer 1

[] denote an array, so if your top-level object for serialization is List you cannot avoid having them. If you want to have top-level item as plain objects you need to rewrite the code adding one more POJO:

public class ItemsContainer {
    private List<Items> itemsList;
}

public class Items {
    private List<Item> items;
    private Boolean isBoolean;
}

List<Items> itemsList= new ArrayList<>();
itemsList.add(new Items(items, isBoolean));

ItemContainer container = new ItemContainer();
container.setItemsList(itemsList);

ObjectMapper mapper = new ObjectMapper();
String itemsJson = mapper.writeValueAsString(container);