如何将二维数组初始化为类变量？

private static int[][] matrix;

static {
    matrix = new int[][] {
        {1, 2, 3},
        {4, 5, 6},
        {7, 8, 9}
    };
}

public static void printMatrix() {
    for (int i = 0; i < matrix.length; i++) {
        for (int j = 0; j < matrix[i].length; j++) {
            System.out.print(matrix[i][j] + " ");
        }
        System.out.println();
    }
}