How can I find duplicates in a Java array?

How can I find duplicates in a Java array?

You can use a HashSet to track duplicates. As you iterate through the array, add elements to the set and check if they already exist.

Can you show me a code example?

Sure! Here's a simple example:

import java.util.HashSet;

public class DuplicateFinder {
    public static void main(String[] args) {
        int[] array = {1, 2, 3, 2, 4, 5, 1};
        HashSet<Integer> set = new HashSet<>();
        for (int num : array) {
            if (!set.add(num)) {
                System.out.println("Duplicate found: " + num);
            }
        }
    }
}

What if I want to find all duplicates, not just the first one?

You can use a HashMap to count occurrences. Then, iterate through the map to find numbers that appear more than once.