有没有一种方法可以缩短这些命令，这样我就不需要重复给每个所有者提供list.add了？

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class Main {
    public static void main(String[] args) {
        List<Owner> owners = new ArrayList<>();
        owners.add(new Owner("Alice", "item1"));
        owners.add(new Owner("Bob", "item2"));
        owners.add(new Owner("Alice", "item3"));
        owners.add(new Owner("Bob", "item4"));

        Map<String, List<Owner>> ownerMap = owners.stream()
                .collect(Collectors.groupingBy(Owner::getName));

        System.out.println(ownerMap);
    }
}

class Owner {
    private String name;
    private String item;

    public Owner(String name, String item) {
        this.name = name;
        this.item = item;
    }

    public String getName() {
        return name;
    }

    public String getItem() {
        return item;
    }

    @Override
    public String toString() {
        return "Owner{" +
                "name='" + name + '\'' +
                ", item='" + item + '\'' +
                '}';
    }
}

{Bob=[Owner{name='Bob', item='item2'}, Owner{name='Bob', item='item4'}], Alice=[Owner{name='Alice', item='item1'}, Owner{name='Alice', item='item3'}]}