How do I find the closest possible sum of an Array's elements to a particular value?

Question

In Java, how should I find the closest (or equal) possible sum of an Array\'s elements to a particular value K?

For example, for the array {19,23,41,5,40,36} and K=4

Answer 1

private int closestSum(int[] a, int num){
    int k=a.length-1;
    int sum=0;
    Arrays.sort(a);

    while(a[k]>num){
        k--;
    }
    for(int i=0;isum)
                sum = a[i]+a[j];
        }
    }
    return sum;
}