Java sort ArrayList with custom fields by number and alphabetically

Question

public class Product implements Serializable{

    private String id;
    private String name;
    private double price ;
    private int quantity;

    public Produ         


        

Answer 1

Use a Comparator, here implemented anonymously (suitable for java 7 and earlier):

List list;
Collections.sort(list, new Comparator() {
    public int compare(Product a, Product b) {
        if (a.getPrice() == b.getPrice())
            return a.getName().compareTo(b.getName()); 
        return a.getPrice() > b.getPrice() ? 1 : a.getPrice() < b.getPrice() ? -1 : 0
    }
});

Java 8 has a much cleaner way of achieving the above:

Collections.sort(list, Comparator.comparing(Product::getPrice).thenComparing(Product::getName));

If this defines the "natural order" of your products, consider making Product implement Comparable and implement it in the compareTo() method of Product.