Java Arrays Quiz | 25 Coding MCQs for Interviews & Exams

STUDYECRAT Java : Arrays

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Java : Arrays

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Q1/4

What is the output?

System.out.println("Hello World");

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★ Java Arrays: Key Interview Points

1. Array Declaration & Initialization

int[] numbers = new int[5]; // Fixed-size array
String[] names = {"Alice", "Bob", "Charlie"}; // Inline initialization
// Arrays are zero-indexed in Java

• Tip: Use Arrays.toString(arr) to print arrays directly.
• Real Use: Storing fixed-size data like days of the week or game levels.

2. Multidimensional Arrays

int[][] matrix = new int[3][3]; // 3x3 grid
matrix[0][0] = 1; // First row, first column
// Jagged arrays (rows with varying columns) are allowed

• Tip: Use nested loops (for-for) to traverse 2D arrays.
• Real Use: Representing grids (e.g., chessboard, spreadsheet data).

3. Array Copying & Cloning

int[] source = {1, 2, 3};
int[] dest = Arrays.copyOf(source, source.length); // Deep copy
// Modifying 'dest' won't affect 'source'

• Tip: System.arraycopy() is faster for large arrays.
• Real Use: Backup/restore operations or thread-safe data handling.

4. Sorting & Searching

int[] nums = {5, 3, 9, 1};
Arrays.sort(nums); // Sorts in-place: [1, 3, 5, 9]
int index = Arrays.binarySearch(nums, 5); // Returns 2
// binarySearch requires a sorted array

• Tip: For custom sorting, use Comparator with object arrays.
• Real Use: Leaderboard rankings or autocomplete suggestions.

5. Arrays vs. ArrayList

String[] arr = {"A", "B"}; // Fixed size
ArrayList<String> list = new ArrayList<>(Arrays.asList(arr)); // Dynamic size
list.add("C"); // Allowed
// Use Arrays for performance, ArrayList for flexibility

• Tip: Convert between them using Arrays.asList() and toArray().
• Real Use: Arrays for CPU-intensive tasks, ArrayList for dynamic data.

💡 Pro Interview Tip

When asked about arrays, always mention their fixed-size limitation and alternatives like ArrayList. Interviewers often test your knowledge of trade-offs!