How to find the boundary elements of a matrix

import java.util.Arrays;
public class Main{
    private static void printBoundaryElements(int[][] matrix){
        // get the number of rows in the matrix
        int numRows = matrix.length;
        // get the number of columns in the matrix
        int numCols = matrix[0].length;
        // Loop through every row in the matrix
        for(int i = 0; i < numRows; i++)
        {
            // Loop through every column in the matrix
            for(int j = 0; j < numCols; j++)
            {
                // check whether the condition for boundary element is true
                if (i == 0 || j == 0 || i == numRows - 1  || j == numCols - 1)
                    System.out.print(matrix[i][j] + " ");
                else
                    System.out.print("  ");
            }
            System.out.println();
        }
    }
    private static void printMatrix(int[][] matrix){
        for (int[] row : matrix)
            System.out.println(Arrays.toString(row));
    }
    public static void main(String[] args){
        int matrix[][] = {{1, 2, 3, 4},
                {4, 5, 6, 5},
                {7, 8 , 9, 6}
        };
        printMatrix(matrix);
        System.out.println("The boundary elements of the above matrix is as follows:");
        printBoundaryElements(matrix);
    }
}