How do you sort an ArrayList alphabetically in Java?

Posted on by Muna Meyer

How do you sort an ArrayList alphabetically in Java?

To sort the ArrayList, you need to simply call the Collections. sort() method passing the ArrayList object populated with country names. This method will sort the elements (country names) of the ArrayList using natural ordering (alphabetically in ascending order). Lets’s write some code for it.

How do I sort a custom Comparator?

Using a comparator, we can sort the elements based on data members. For instance, it may be on roll no, name, age, or anything else. Method of Collections class for sorting List elements is used to sort the elements of List by the given comparator.

How do you alphabetize an ArrayList?

An ArrayList can be sorted by using the sort() method of the Collections class in Java. It accepts an object of ArrayList as a parameter to be sort and returns an ArrayList sorted in the ascending order according to the natural ordering of its elements.

How do you sort a list alphabetically in Java?

Sort a List Alphabetically in Java

  1. Sort a List Using the Collections.sort() Method in Java.
  2. Sort a List Using the list.stream().sorted() Method in Java 8.
  3. Sort a List Using the Guava Library in Java.
  4. Sort a List Using the Comparator.naturalOrder() in Java.
  5. Sort a List Using the String Class in Java.

How do you use comparator for descending order?

In order to sort ArrayList in Descending order using Comparator, we need to use the Collections. reverseOrder() method which returns a comparator which gives the reverse of the natural ordering on a collection of objects that implement the Comparable interface.

How do you call a Comparator in Java?

NameComparator.java

  1. import java.util.*;
  2. class NameComparator implements Comparator{
  3. public int compare(Object o1,Object o2){
  4. Student s1=(Student)o1;
  5. Student s2=(Student)o2;
  6. return s1.name.compareTo(s2.name);
  7. }
  8. }

How do you create a custom sort method in Java?

Java Custom Sorting With Employee Objects First, Create Employee class with id, name and age. Next, Implement Comparable interface and provide implementation to compareTo() method.

How do you sort an ArrayList in ascending order in Java?

Approach: An ArrayList can be Sorted by using the sort() method of the Collections Class in Java. This sort() method takes the collection to be sorted as the parameter and returns a Collection sorted in the Ascending Order by default.

Does comparator sort in ascending order?

Comparator is used to sort an ArrayList of User-defined objects. Override the compare() method in such a way that it will reorder an ArrayList in descending order instead of ascending order.

How do you use comparator to sort in descending order in Java?