I found you error.

Code run: http://ideone.com/Nb3DW1

   int a, b, c;
// Ambiguous reference to a,b,c
        public Triplet(int a, int b, int c) {
            int[] tmp = {a, b, c};
            Arrays.sort(tmp);
            a = tmp[0]; b = tmp[1]; c = tmp[2];
        }

 public int a, b, c;
 //No Ambiguos reference to a,b,c.
        public Triplet(int a1, int b1, int c1) {
            int[] tmp = {a1, b1, c1};
            Arrays.sort(tmp);
            a = tmp[0]; b = tmp[1]; c = tmp[2];
        }