How to Remove Duplicates in a List in Java - Step by Step Examples

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How to Remove Duplicates in a List in Java ?

Answer

To remove duplicates in a list in Java, you can use a Set to automatically eliminate duplicates.

✐ Examples

1 Remove Duplicates from Integer List

In this example,

We create a list named numbers with integer values.
We create a HashSet and add all elements of the list to it.
We convert the HashSet back to a list to preserve the order of elements.
Finally, we print the list without duplicates to standard output.

Java Program

import java.util.*;

public class Main {
    public static void main(String[] args) {
        List<Integer> numbers = Arrays.asList(1, 2, 2, 3, 4, 4, 5);
        Set<Integer> uniqueNumbers = new HashSet<>(numbers);
        List<Integer> distinctNumbers = new ArrayList<>(uniqueNumbers);
        System.out.println("List without duplicates: " + distinctNumbers);
    }
}

Output

List without duplicates: [1, 2, 3, 4, 5]

2 Remove Duplicates from String List

In this example,

We create a list named words with string values.
We create a HashSet and add all elements of the list to it.
We convert the HashSet back to a list to preserve the order of elements.
Finally, we print the list without duplicates to standard output.

Java Program

import java.util.*;

public class Main {
    public static void main(String[] args) {
        List<String> words = Arrays.asList("apple", "banana", "cherry", "apple", "banana");
        Set<String> uniqueWords = new HashSet<>(words);
        List<String> distinctWords = new ArrayList<>(uniqueWords);
        System.out.println("List without duplicates: " + distinctWords);
    }
}

Output

List without duplicates: [apple, banana, cherry]

Summary

In this tutorial, we learned How to Remove Duplicates in a List in Java language with well detailed examples.

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How to Remove Duplicates in a List in Java - Step by Step Examples

How to Remove Duplicates in a List in Java ?

Answer

✐ Examples

1 Remove Duplicates from Integer List

Java Program

Output

2 Remove Duplicates from String List

Java Program

Output

Summary

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