Java List Sorting: How to Sort ArrayLists and LinkedLists

Learn how to sort Java lists such as ArrayList and LinkedList using the Collections class from the java.util package. Discover methods to sort elements, including sorting an ArrayList of Strings in ascending alphabetical order, and improve data organization in Java applications.

Java List Sorting

In Java, you can sort lists like ArrayList and LinkedList using the Collections class from the java.util package.

Sort an ArrayList

To sort an ArrayList of Strings alphabetically in ascending order:

Syntax


import java.util.ArrayList;
import java.util.Collections;  // Import the Collections class

public class Main {
  public static void main(String[] args) {
    ArrayList<String> cars = new ArrayList<>();
    cars.add("Volvo");
    cars.add("BMW");
    cars.add("Ford");
    cars.add("Mazda");

    Collections.sort(cars);  // Sort cars

    for (String i : cars) {
      System.out.println(i);
    }
  }
}

Output


BMW
Ford
Mazda
Volvo

To sort an ArrayList of Integers numerically in ascending order:

Syntax


import java.util.ArrayList;
import java.util.Collections;  // Import the Collections class

public class Main {
  public static void main(String[] args) {
    ArrayList<Integer> myNumbers = new ArrayList<>();
    myNumbers.add(33);
    myNumbers.add(15);
    myNumbers.add(20);
    myNumbers.add(34);
    myNumbers.add(8);
    myNumbers.add(12);

    Collections.sort(myNumbers);  // Sort myNumbers

    for (int i : myNumbers) {
      System.out.println(i);
    }
  }
}

Output

Reverse the Order

To sort a list in reverse order, use the Collections.reverseOrder() method:

Sorting an ArrayList of Strings in reverse/descending order:

Syntax


import java.util.ArrayList;
import java.util.Collections;  // Import the Collections class

public class Main {
  public static void main(String[] args) {
    ArrayList<String> cars = new ArrayList<>();
    cars.add("Volvo");
    cars.add("BMW");
    cars.add("Ford");
    cars.add("Mazda");

    Collections.sort(cars, Collections.reverseOrder()); // Sort cars in reverse order

    for (String i : cars) {
      System.out.println(i);
    }
  }
}

Output


Volvo
Mazda
Ford
BMW

Sorting an ArrayList of Integers in reverse/descending order:

Syntax


import java.util.ArrayList;
import java.util.Collections;  // Import the Collections class

public class Main {
  public static void main(String[] args) {
    ArrayList<Integer> myNumbers = new ArrayList<>();
    myNumbers.add(33);
    myNumbers.add(15);
    myNumbers.add(20);
    myNumbers.add(34);
    myNumbers.add(8);
    myNumbers.add(12);

    Collections.sort(myNumbers, Collections.reverseOrder()); // Sort myNumbers in reverse order

    for (int i : myNumbers) {
      System.out.println(i);
    }
  }
}

Output