Code

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        int[][] ARRAY = new int[][]{
              { 4, -3, 356 },
              { 44, -2, 32 },
              { 91, -3, 34 }
            };

        int SMALLEST = 9999;
        int CURRENTDIF = 0;
        int[][] SMALLINDEX = {
                {0, 0},
                {0, 0}
        };


            for(int ROW = 0; ROW < ARRAY.length; ROW++) {
                for (int COL = 0; COL < ARRAY[ROW].length-1; COL++) {
                    if (COL != ARRAY[ROW].length) {
                        CURRENTDIF = ARRAY[ROW][COL] - ARRAY[ROW][COL+1];
                        System.out.println("ARRAY[" + ROW + "][" + COL + "]-ARRAY[" + ROW + "][" + (COL+1) + "] = " + Math.abs(CURRENTDIF));
                        if (Math.abs(CURRENTDIF) < SMALLEST) {
                            SMALLEST = Math.abs(CURRENTDIF);
                            SMALLINDEX[0][0] = ROW;
                            SMALLINDEX[0][1] = COL;
                            SMALLINDEX[1][0] = ROW;
                            SMALLINDEX[1][1] = COL+1;
                        }
                    }
                }
            }

            System.out.println("The smallest difference is " + SMALLEST + " between the elements of ARRAY[" + SMALLINDEX[0][0] + "]" + "[" + SMALLINDEX[0][1] + "] and ARRAY[" + SMALLINDEX[1][0] + "][" + SMALLINDEX[1][1] + "]");


    }
}