Remove Duplicates from a List in Java

We can remove duplicates from a List in Java in the following ways:

• By converting the List into a Set
• Using Java 8 Streams
  

Remove duplicates from a List in Java by converting the List into a Set

A Set is a Collection that cannot contain duplicate elements. When we convert a List into a Set, all duplicates will be removed.

import java.util.*;

public class Test {

  public static void main(String[] args) {

    List<String> names = new ArrayList<>(Arrays.asList("Megan", "Tom", "Steve", "Megan", "Meliisa", "Tom", "John"));

    Set<String> uniqueNames = new HashSet<>(names); // creating a Set from the List

    System.out.println(uniqueNames);
  }
}

Remove duplicates from a List in Java using the Java 8 Streams

Below is the program where we use distinct() method from the Streams API to remove duplicate elements from a list:

import java.util.*;
import java.util.stream.Collectors;

public class Test {

  public static void main(String[] args) {

    List<String> names = new ArrayList<>(Arrays.asList("Megan", "Tom", "Steve", "Megan", "Meliisa", "Tom", "John"));

    List<String> uniqueNames = names.stream().distinct().collect(Collectors.toList());

    System.out.println(uniqueNames);
  }
}