Triplet sum closest to target

Input: a[] = [-2, -4, 6, 3, 7], target = 2
Output: 1
Explanation: Triplet with sum closest to target is [-2, -4, 7], sum of the triplets = 1

Input: a[] = [10, 2, 30, 49, 8], target = 50
Output: 48
Explanation: Triplet with sum closest to target is [10, 30, 8], sum of the triplets = 48

Input: a[] = [1, 0, 5, 0, 3], target = 100
Output: 9

import java.util.Arrays;
import java.util.Scanner;

public class TripletSumClosestToTarget {
    private static int findTripletSumClosestToTarget(int[] a, int targetSum) {
        Arrays.sort(a);
        int smallestDiff = Integer.MAX_VALUE;
        
        for(int i = 0; i < a.length-2; i++) {
            // Skip duplicates
            if(i > 0 && a[i] == a[i-1]) {
                continue;
            }

            // Fix one number
            int firstNum = a[i];

            // Use Two-sum approach to get the other two numbers 
            // such that the sum of all three numbers are closest to target
            int left = i+1, right = a.length-1;
            while(left < right) {
                int currentSum = firstNum + a[left] + a[right];
                int currentDiff = targetSum-currentSum;

                if(currentDiff == 0) {
                    return currentSum;
                }
                
                if(Math.abs(currentDiff) < Math.abs(smallestDiff)) {
                    smallestDiff = currentDiff;
                }
                
                if (currentDiff > 0) { 
                    // TargetSum is greater than the sum of triplets. 
                    // Increment left pointer to increase the sum so that the difference moves closer to zero
                    left++;
                } else {
                    // TargetSum is smaller than the sum of triplets.
                    // Decrement right pointer to decrease the sum  so that the difference moves closer to zero                 
                    right--;
                }
            }
        }

        return targetSum-smallestDiff;
    }

    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        int n = keyboard.nextInt();
        int[] a = new int[n];
        for(int i = 0; i < n; i++) {
            a[i] = keyboard.nextInt();
        }
        int targetSum = keyboard.nextInt();
        keyboard.close();

        System.out.printf("Triplet sum closest to target = %d%n", findTripletSumClosestToTarget(a, targetSum));
    }
}