How to Sort an ArrayList of Custom Objects in Java Based on a Specific Property?

How to Sort an ArrayList of Custom Objects in Java

Sorting an ArrayList of custom objects involves comparing the objects based on specific properties. In this case, we have a list of Fruit objects, and we want to sort them based on their fruit names.

Creating the Fruit Class and ArrayList

We start by defining the Fruit class with its attributes and getters/setters:

public class Fruit {
    private String fruitName;
    private String fruitDesc;
    private int quantity;
    // getters and setters
}

// Create an ArrayList of Fruit
List<Fruit> fruits = new ArrayList<>();

Adding Fruits to the ArrayList

We populate the ArrayList using a loop:

Fruit fruit;
for (int i = 0; i < 100; i++) {
    fruit = new Fruit();
    // set fruit properties
    fruits.add(fruit);
}

Sorting the ArrayList

To sort the ArrayList based on fruit names, we use the Collections.sort method and a custom Comparator:

Collections.sort(fruits, new Comparator<Fruit>() {
    @Override
    public int compare(Fruit fruit1, Fruit fruit2) {
        return fruit1.getFruitName().compareTo(fruit2.getFruitName());
    }
});

In the Comparator, we use the compareTo method to compare the fruit names of the two fruits and return an integer based on the result:

• If fruit1's name comes before fruit2's name in alphabetical order, it returns a negative integer.
• If fruit1's name comes after fruit2's name in alphabetical order, it returns a positive integer.
• If both names are the same, it returns 0.

After sorting, the fruits ArrayList will contain the Fruit objects ordered alphabetically by their fruit names.

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