Java Program to remove duplicates from ArrayList

Sample program to learn how to remove duplicates from ArrayList. 
The steps followed in the below example are:
Copying all the elements of ArrayList to LinkedHashSet.
Why we choose LinkedHashSet? Because it removes duplicates and maintains the insertion order.
Emptying the ArrayList, you can use clear() method to remove all elements of ArrayList and start fresh.
Copying all the elements of LinkedHashSet (non-duplicate elements) to the ArrayList.

public class ArrayListDuplicateDemo {
    public static void main(String args[]) {
        // creating ArrayList with duplicate elements
        List<Integer> primes = new ArrayList<Integer>();
        primes.add(2);
        primes.add(3);
        primes.add(5);
        primes.add(7); //duplicate
        primes.add(7);
        primes.add(11); // let's print arraylist with duplicate
        System.out.println("list of prime numbers : " + primes);
        // Now let's remove duplicate element without affecting order
        // LinkedHashSet will guaranteed the order and since it's set
        // it will not allow us to insert duplicates.
        // repeated elements will automatically filtered.
        Set<Integer> primesWithoutDuplicates = new LinkedHashSet<Integer>(primes);
        // now let's clear the ArrayList so that we can copy all elements from LinkedHashSet
        primes.clear(); // copying elements but without any duplicates
        primes.addAll(primesWithoutDuplicates);
        System.out.println("list of primes without duplicates : " + primes);
    }
}

Output list of prime numbers :[2,3,5,7,7,11]
list of primes without duplicates :[2,3,5,7,11]