Java 2D Array Mastery

How do you access the element in the second row and third column of a Java 2D array named `array`?

• `array[1][2]`

• `array[2][3]`

• `array[3][2]`

• `array[2][1]`

What is the initial value of an int type element in a Java 2D array if it is not explicitly initialized?

• `0`

• `1`

• `null`

• `undefined`

Which of the following is the correct way to declare a 2D array in Java?

• `int[][] array = new int[5][5];`

• `int array[][] = new int[][];`

• `int[5][5] array = new int[][];`

• `int array = new int[5][5];`

How would you set the value `10` to the first element in the first row of a 2D array named `matrix`?

• `matrix[0][0] = 10;`

• `matrix[1][1] = 10;`

• `matrix[0] = 10;`

• `matrix = 10;`

What does the following code snippet print? ```java int[][] numbers = {{1, 2}, {3, 4}, {5, 6}}; System.out.println(numbers[1][1]); ```

• `2`

• `3`

• `4`

• `6`

Which loop structure is commonly used to traverse a 2D array in Java?

• A single `for` loop

• A single `while` loop

• Nested `for` loops

• Recursive method calls

If you have a 2D array `int[][] grid = new int[3][2];`, what is the total number of elements in the array?

• `3`

• `2`

• `5`

• `6`

How do you initialize a 2D array with the numbers 1 through 9 in a 3x3 grid?

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

• `int[][] grid = new int[1, 2, 3, 4, 5, 6, 7, 8, 9];`

• `int[][] grid = new int[3][3]{1, 2, 3, 4, 5, 6, 7, 8, 9};`

• `int[][] grid = new int[]{1, 2, 3, 4, 5, 6, 7, 8, 9};`

What is the result of trying to access an element outside the bounds of a 2D array?

• A `NullPointerException` is thrown.

• A `NegativeArraySizeException` is thrown.

• An `ArrayIndexOutOfBoundsException` is thrown.

• The program compiles and runs without any errors.

Which of the following statements is true about a 2D array in Java?

• A 2D array can have rows of different lengths.

• A 2D array must have all rows of the same length.

• A 2D array is always square (same number of rows and columns).

• A 2D array cannot contain primitive data types.