Java Array Coding Questions and Answers

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Welcome to the Java Array Coding Quiz. In this quiz, we present 10 coding MCQ questions to test your coding knowledge on the Java Array topic. Each question has a correct and brief explanation.

1. What is the output of the following Java code snippet?

int[] array = {1, 2, 3, 4, 5};
System.out.println(array[2]);

a) 1

b) 2

c) 3

d) 4

Answer:

c) 3

Explanation:

Arrays in Java are zero-indexed. array[2] refers to the third element in the array, which is 3.

2. What does this Java code snippet output?

int[] numbers = new int[5];
System.out.println(numbers[3]);

a) 0

b) 3

c) 4

d) Null

Answer:

a) 0

Explanation:

In Java, integer arrays are initialized with default values of 0 for each element. numbers[3] refers to the fourth element, which is 0.

3. Identify the output of the following code:

int[] nums = {1, 2, 3, 4, 5};
for (int i = 0; i < nums.length; i++) {
    nums[i] = nums[i] * 2;
}
System.out.println(nums[2]);

a) 3

b) 4

c) 6

d) 8

Answer:

c) 6

Explanation:

The loop doubles each element of the array. So, nums[2], which was initially 3, becomes 6.

4. What will be printed by this Java code?

int[] array = new int[]{1, 2, 3, 4, 5};
System.out.println(array[array.length - 1]);

a) 1

b) 4

c) 5

d) An error

Answer:

c) 5

Explanation:

array.length is 5, so array[array.length - 1] is array[4], which is the last element of the array, 5.

5. What does this code snippet output?

int[][] matrix = {{1, 2}, {3, 4}, {5, 6}};
System.out.println(matrix[1][1]);

a) 2

b) 3

c) 4

d) 6

Answer:

c) 4

Explanation:

matrix[1][1] accesses the second element of the second array, which is 4.

6. What is the result of executing this code?

int[] numbers = {1, 2, 3, 4, 5};
System.out.println(numbers[numbers.length]);

a) 1

b) 5

c) An ArrayIndexOutOfBoundsException

d) Null

Answer:

c) An ArrayIndexOutOfBoundsException

Explanation:

Accessing numbers[numbers.length] attempts to access an index outside the bounds of the array, resulting in an ArrayIndexOutOfBoundsException.

7. What will the following Java code snippet output?

int[] array = {1, 2, 3, 4, 5};
int[] anotherArray = array;
anotherArray[0] = 10;
System.out.println(array[0]);

a) 1

b) 10

c) 2

d) An error

Answer:

b) 10

Explanation:

anotherArray is a reference to the same array as the array. Changing an element via anotherArray will affect the array as well.

8. What does the following code snippet print?

int[] numbers = {1, 2, 3, 4, 5};
int sum = 0;
for (int number : numbers) {
    sum += number;
}
System.out.println(sum);

a) 10

b) 15

c) 20

d) 25

Answer:

b) 15

Explanation:

This code calculates the sum of all elements in the array, which is 15.

9. Determine the output of this Java code:

int[] values = new int[3];
values[0] = 10;
values[1] = 20;
System.out.println(values[2]);

a) 0

b) 10

c) 20

d) Null

Answer:

a) 0

Explanation:

The array is initialized with default integer values (0). Since values[2] is not explicitly set, it remains 0.

10. What is the result of the following code snippet?

int[] arr = {1, 2, 3, 4, 5};
int x = arr[1] + arr[4];
System.out.println(x);

a) 3

b) 6

c) 7

d) 9

Answer:

c) 7

Explanation:

arr[1] is 2 and arr[4] is 5. Their sum, 2 + 5, is 7.