What are the ways to define a two-dimensional array in Java?

There are several ways to define a two-dimensional array in Java.

1. Using static initialization method:

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

1. Initialize using a dynamic method:

int[][] arr = new int[3][3];
arr[0] = new int[]{1, 2, 3};
arr[1] = new int[]{4, 5, 6};
arr[2] = new int[]{7, 8, 9};

1. Defining the length of an array.

int[][] arr = new int[3][3];

1. Initialization using a for loop:

int[][] arr = new int[3][3];
for (int i = 0; i < arr.length; i++) {
    for (int j = 0; j < arr[i].length; j++) {
        arr[i][j] = i * arr.length + j + 1;
    }
}