Array — Part 1 MCQs with Explanations

In Java, a one-dimensional array is declared by specifying the type of elements followed by square brackets and then the array name. The correct syntax is: type[] arrayName; Option A follows this syntax and is the correct way to declare a one-dimensional array in Java. Option B is also a valid syntax but is less commonly used. Both Option A and Option B are equivalent. Option C is incorrect as it attempts to use generics syntax, which is not allowed for arrays in Java. Option D is incorrect because Option C is not a valid way to declare an array.

Option A initializes a String array named "names" with three elements: "Alice", "Bob", and "Charlie". This is a valid and commonly used syntax for declaring and initializing a String array in Java. Option B: String names[] = new String[]{"Alice", "Bob", "Charlie"}; This syntax is also valid for declaring and initializing a String array in Java. However, it's less commonly used. Option C: String[3] names = {"Alice", "Bob", "Charlie"}; This syntax is invalid. In Java, when declaring an array, the size should not be specified in the square brackets.

In Java, arrays are objects. They are instances of classes that extend the abstract class java.lang.Object. However, arrays in Java are implemented as objects of a specific type called "Array". This means that arrays in Java are indeed objects, but they are not instances of the Array class; rather, they are instances of classes that are automatically generated by the Java Virtual Machine (JVM) when arrays are created. Option A: Arrays can change in size after initialization. In Java, once an array is initialized with a specific size, that size cannot be changed. Arrays have a fixed length determined at the time of creation. While you can create a new array with a different size and copy elements from the old array to the new one to achieve a similar effect, the original array itself cannot change its size. Option B: Arrays can store elements of different types. In Java, arrays are homogeneous data structures, meaning they can only store elements of the same type. When you declare an array, you specify the type of elements it can hold. All elements in the array must be compatible with this type. Option C: Arrays can have a negative length. In Java, array lengths must be non-negative integers. It is not possible to declare an array with a negative length. Attempting to do so will result in a compilation error. Therefore, the correct answer is Option D: Arrays are objects of type Array. Arrays in Java are indeed objects, but they are instances of classes that are automatically generated by the Java Virtual Machine (JVM) when arrays are created. They are not instances of the Array class itself, but they are objects nonetheless.

In java an array is a container object that holds a fixed number of values of a single type. The length of an array is established when the array is created. After creation, its length is fixed.

The syntax for declaring and creating an array variable in java is: dataType[] arrayRefVar = new dataType[arraySize]; Thus, option (A) and option (C) is syntactically wrong as parentheses( ( ) ) is used instead of square brackets( [ ] ). Option (D) is incorrect as the size of the array is missing.

Step 1: Declare a public class named Test . Step 2: Define the main method with the public and static modifiers and a parameter of type String array named args . Step 3: Declare an array variable a of type int[] . Step 4: Initialize the array a with a size of 0 using the new keyword. Step 5: Print the length of the array a using the length property. Therefore, when you compile and run the code, the output will be: 0 This output corresponds to the length of the array a , which is 0.

Program is syntactically correct, so no error. In java, if the array is not initialized at the time of declaration and creation then all the elements of the array are initialized to 0 by default.

In the given program. Line 7 : if(myList[i] > max) execute only on time when i =1; when i = 1 then myList[i] = 5 and max = 1( so the statement is true and if block will be executed ). Then, max = myList[i] = 5 and indexOfMax = i = 1. After that if statement always false. so indexOfMax value remain 1. Therefore the value of indexOfMax is 1 at end of the for loop.

016 is an octal number. The prefix 0 indicates that a number is in octal.

After executing the statement a = new int [ 2 ], a refers to int [ 2 ]. The default value for a [ 0 ] and a [ 1 ] is 0.

new double []{1, 2, 3} is correct. This is the syntax I have not covered in this edition, but will be covered in the future edition. In this question, double [] x = new double []{1, 2, 3} is equivalent to double [] x = {1, 2, 3};

The only legal array declaration and assignment statement is Option D Option A is wrong because it initializes an int array with String literals. Option B is wrong because it uses something other than curly braces for the initialization. Option C is wrong because it provides initial values for only one dimension, although the declared array is a two-dimensional array.

An exception is thrown because in the code String s4 = args [ 4 ];, the array index (the fifth element) is out of the bounds. The exception thrown is the ArrayIndexOutOfBoundsException .

Here's an explanation of the code: 1. The array a is initialized with values: {0, 2, 4, 1, 3}. 2. The for loop iterates over each element of the array using the variable i . 3. Inside the loop, the value of a[i] is updated using the expression a[(a[i] + 3) % a.length] . (i) For i = 0 , a[i] is 0. So, a[(0 + 3) % 5] becomes a[3 % 5] which is a[3] (value 1). (ii) For i = 1 , a[i] is 2. So, a[(2 + 3) % 5] becomes a[5 % 5] which is a[0] (value 0). (iii) For i = 2 , a[i] is 4. So, a[(4 + 3) % 5] becomes a[7 % 5] which is a[2] (value 4). (iv) For i = 3 , a[i] is 1. So, a[(1 + 3) % 5] becomes a[4 % 5] which is a[4] (value 3). (v) For i = 4 , a[i] is 3. So, a[(3 + 3) % 5] becomes a[6 % 5] which is a[1] (value 2). 4. After the loop finishes, the modified array a becomes {0, 1, 4, 3, 2}. 5. Finally, the code prints the value of a[1] using System.out.println(a[1]) , which outputs 1 . Therefore, the output of the code is 1 .

An array is always an instance of Object.

None of the above is the correct answer to “In Java, arrays are objects of which class”. This question is standard in competitive examination syllabi for Array.

0 is the correct answer to “What is the default initial value of numeric elements in an array of type int in Java”. This question is standard in competitive examination syllabi for Array.

int[][] myArray = {{1, 2}, {3, 4}} is the correct answer to “What is the correct way to initialize a two-dimensional array in Java”. This question is standard in competitive examination syllabi for Array.

The number of elements in the array is the correct answer to “What does the length attribute of an array in Java represent”. This question is standard in competitive examination syllabi for Array.

myArray[3] is the correct answer to “How do you access an element in a one-dimensional array named myArray at index 3 in Java”. This question is standard in competitive examination syllabi for Array.

It throws an ArrayIndexOutOfBoundsException. is the correct answer to “What happens if you try to access an array element at an index that is out of bounds in Java”. This question is standard in competitive examination syllabi for Array.

length is the correct answer to “Which method is used to find the length of an array in Java”. This question is standard in competitive examination syllabi for Array.

9 is the correct answer to “What is the highest index of an array with 10 elements in Java”. This question is standard in competitive examination syllabi for Array.

matrix.length is the correct answer to “How do you find the number of rows in a two-dimensional array named matrix in Java”. This question is standard in competitive examination syllabi for Array.

FALSE is the correct answer to “What is the default initial value of elements in an array of type boolean in Java”. This question is standard in competitive examination syllabi for Array.

Use a for loop to iterate through the elements and copy them one by one. is the correct answer to “What is the correct way to copy the elements of one array to another in Java”. This question is standard in competitive examination syllabi for Array.

int[] numbers = new int[5] is the correct answer to “How do you declare and initialize an array of integers with 5 elements in Java”. This question is standard in competitive examination syllabi for Array.

ArrayList numbers[] = new ArrayList[5] is the correct answer to “How do you declare a dynamic array (ArrayList) of integers in Java”. This question is standard in competitive examination syllabi for Array.

To copy elements from one array to another. is the correct answer to “What is the purpose of the System.arraycopy() method in Java”. This question is standard in competitive examination syllabi for Array.

The size can change dynamically. is the correct answer to “Which of the following is true about the size of an ArrayList in Java”. This question is standard in competitive examination syllabi for Array.

list.remove(index) is the correct answer to “In Java, how do you remove an element at a specific index from an ArrayList named list”. This question is standard in competitive examination syllabi for Array.

Use the contains() method. is the correct answer to “How do you check if an element exists in an array or ArrayList in Java”. This question is standard in competitive examination syllabi for Array.

To sort the elements of an array. is the correct answer to “What is the purpose of the Arrays.sort() method in Java”. This question is standard in competitive examination syllabi for Array.

list.indexOf(element) is the correct answer to “How do you find the index of an element in an ArrayList named list in Java”. This question is standard in competitive examination syllabi for Array.

add() is the correct answer to “Which method is used to add an element to the end of an ArrayList in Java”. This question is standard in competitive examination syllabi for Array.

It throws an ArrayIndexOutOfBoundsException. is the correct answer to “What happens when you try to access an element at an index that is out of bounds in an ArrayList in Java”. This question is standard in competitive examination syllabi for Array.

clear() is the correct answer to “Which method is used to remove all elements from an ArrayList in Java”. This question is standard in competitive examination syllabi for Array.

Use a loop to compare each element with the maximum value found so far. is the correct answer to “In Java, how do you find the maximum element in an array”. This question is standard in competitive examination syllabi for Array.

ArrayLists can have duplicate elements. is the correct answer to “Which of the following statements is true about ArrayLists in Java”. This question is standard in competitive examination syllabi for Array.

All of the above is the correct answer to “How do you declare a multi-dimensional array in Java”. This question is standard in competitive examination syllabi for Array.