Java Questions & Answers – Arrays

This section of our 1000+ Java MCQs focuses on Array Data Structure of Java Programming Language.

1. Which of these operators is used to allocate memory to array variable in Java?
a) malloc
b) alloc
c) new
d) new malloc
View Answer

Answer:c
Explanation:Operator new allocates block of memory specified by the size of array, and gives the reference of memory allocated to the array variable.

2. Which of these is an incorrect array declaration?
a) int arr[] = new int[5]
b) int [] arr = new int[5]
c) int arr[]
arr = new int[5]
d) int arr[] = int [5] new
View Answer

Answer:d
Explanation:Operator new must be succeeded by array type and array size.

3. What will this code print?
int arr[] = new int [5];
System.out.print(arr);
a) 0
b) value stored in arr[0].
c) 00000
d) Garbage value
View Answer

Answer:d
Explanation:arr is an array variable, it is pointing to array if integers. Printing arr will print garbage value. It is not same as printing arr[0].

4. Which of these is an incorrect Statement?
a) It is necessary to use new operator to initialize an array.
b) Array can be initialized using comma separated expressions surrounded by curly braces.
c) Array can be initialized when they are declared.
d) None of the mentioned
View Answer

Answer: a
Explanation:Array can be initialized using both new and comma separated expressions surrounded by curly braces example : int arr[5] = new int[5]; and int arr[] = { 0, 1, 2, 3, 4};

5. Which of these is necessary to specify at time of array initialization?
a) Row
b) Column
c) Both Row and Column
d) None of the mentioned
View Answer

Answer:a
Explanation:None.

6. What is the output of this program?

  1.     class array_output {
  2.         public static void main(String args[]) 
  3.         {
  4.             int array_variable [] = new int[10];
  5. 	    for (int i = 0; i < 10; ++i) {
  6.                 array_variable[i] = i;
  7.                 System.out.print(array_variable[i] + " ");
  8.                 i++;
  9.             }
  10.         } 
  11.     }

a) 0 2 4 6 8
b) 1 3 5 7 9
c) 0 1 2 3 4 5 6 7 8 9
d) 1 2 3 4 5 6 7 8 9 10
View Answer

Answer:a
Explanation:When an array is declared using new operator then all of its elements are initialized to 0 automatically. for loop body is executed 5 times as whenever controls comes in the loop i value is incremented twice, first by i++ in body of loop then by ++i in increment condition of for loop.
output:
$ javac array_output.java
$ java array_output
0 2 4 6 8

7. What is the output of this program?

  1.     class multidimention_array {
  2.         public static void main(String args[])
  3.         {
  4.             int arr[][] = new int[3][];
  5.             arr[0] = new int[1];
  6.             arr[1] = new int[2];
  7.             arr[2] = new int[3];               
  8. 	    int sum = 0;
  9. 	    for (int i = 0; i < 3; ++i) 
  10. 	        for (int j = 0; j < i + 1; ++j)
  11.                     arr[i][j] = j + 1;
  12. 	    for (int i = 0; i < 3; ++i) 
  13. 	        for (int j = 0; j < i + 1; ++j)
  14.                     sum + = arr[i][j];
  15. 	    System.out.print(sum); 	
  16.         } 
  17.     }

a) 11
b) 10
c) 13
d) 14
View Answer

Answer:b
Explanation:arr[][] is a 2D array, array has been allotted memory in parts. 1st row contains 1 element, 2nd row contains 2 elements and 3rd row contains 3 elements. each element of array is given i + j value in loop. sum contains addition of all the elements of the array.
output:
$ javac multidimention_array.java
$ java multidimention_array
10

8. What is the output of this program?

  1.     class evaluate {
  2.         public static void main(String args[]) 
  3.             {
  4. 	        int arr[] = new int[] {0 , 1, 2, 3, 4, 5, 6, 7, 8, 9};
  5. 	        int n = 6;
  6.                 n = arr[arr[n] / 2];
  7. 	        System.out.println(arr[n] / 2);
  8.             } 
  9.     }

a) 3
b) 0
c) 6
d) 1
View Answer

Answer:d
Explanation:Array arr contains 10 elements. n contains 6 thus in next line n is given value 2 printing arr[2]/2 i:e 2/2 = 1.
output:
$ javac evaluate.java
$ java evaluate
1

9. What is the output of this program?

  1.     class array_output {
  2.         public static void main(String args[]) 
  3.         {
  4.             char array_variable [] = new char[10];
  5. 	    for (int i = 0; i < 10; ++i) {
  6.                 array_variable[i] = 'i';
  7.                 System.out.print(array_variable[i] + "");
  8.             }
  9.         } 
  10.     }

a) 1 2 3 4 5 6 7 8 9 10
b) 0 1 2 3 4 5 6 7 8 9 10
c) i j k l m n o p q r
d) i i i i i i i i i i
View Answer

Answer:d
Explanation:None.
output:
$ javac array_output.java
$ java array_output
i i i i i i i i i i

10. What is the output of this program?

  1.     class array_output {
  2.         public static void main(String args[]) 
  3.         {
  4.             int array_variable[][] = {{ 1, 2, 3}, { 4 , 5, 6}, { 7, 8, 9}};
  5.             int sum = 0;
  6.             for (int i = 0; i < 3; ++i)
  7.                 for (int j = 0; j <  3 ; ++j)
  8.                     sum = sum + array_variable[i][j];
  9.             System.out.print(sum / 5);
  10.         } 
  11.     }

a) 8
b) 9
c) 10
d) 11
View Answer

Answer:b
Explanation:None.
output:
$ javac array_output.java
$ java array_output
9

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Manish Bhojasia, a technology veteran with 17+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer and SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage & Cluster Administration, Advanced C Programming, SAN Storage Technologies, SCSI Internals and Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him below.


Sanfoundry Training Center of Excellence (CoE)

Manish Bhojasia, a technology veteran with 17+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer and SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage & Cluster Administration, Advanced C Programming, SAN Storage Technologies, SCSI Internals and Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him below.


1000 Java MCQs | Quiz

Integer and Floating Data Types
Character and Boolean Data Types
Literals & Variables
Type Conversions, Promotions and Castings
Arrays
Arithmetic Operators
Bitwise Operators
Relational Operators and Boolean Logic Operators
Assignment Operators and Operator Precedence
Control Statements
Class Fundamentals & Declaring objects
Introduction to Methods
Constructors & Garbage Collection
Overloading Methods & Argument Passing
Access Control
Arrays Revisited & Keyword static
String Class
Inheritance
Method overriding
The Object Class
String Handling Basics
Character Extraction
String Comparison
Searching & Modifying a String
StringBuffer class
StringBuffer Methods
Packages
Interfaces
Java.lang Introduction
Java.lang - Integer, Long And Character Wrappers
Java.lang - Void, Process and System Class
Java.lang - Object & Math Class
Java.io Introduction
Java.io Byte Streams
Java.io Character Streams
Serialization
Serialization & Deserialization
Networking Basics
URL class
HttpResponse & URLConnection Class
networking - Server, Sockets & httpd Class
networking - httpd.java Class
networking - Datagrams
Java.util - ArrayList Class
Java.util - LinkedList, HashSet & TreeSet Class
Java.util - Maps
Java.util - Array Class
Java.util - Vectors & Stack
Java.util - Dictionary, Hashtable & Properties
Java.util - BitSet & Date class
Methods Taking Parameters
Exceptional Handling Basics
Exceptions Types
Throw, Throws & Nested Try
isAlive(), Join() & Thread Synchronization
Implementing Runnable interface for Threads
Thread class
Multithreading Basics
Networking Basics
Finally & Built in Exceptions
Creating Threads
Input & Output Basics
Reading Console Input
Writing Console Output
Reading & Writing Files
Applets Fundamentals
Core Java API Packages
Remote Method Invocation (RMI)
Text Formatting
Event Handling Basics
ActionEvent & AdjustmentEvent Class
ComponentEvent, ContainerEvent & FocusEvent Class
MouseEvent, TextEvent & WindowEvent Class
Event Listeners Interfaces
Java.lang - Rounding Functions
Java.lang - Miscellaneous Math Methods & StrictMath Class
Java.lang - ThreadGroup class & Runnable Interface
Java.lang - System Class Advance
Java.lang - Double & Float Wrappers
Java.lang - Byte & Short Wrappers
Java.lang - Character Wrapper Advance
Java.lang - Boolean Wrapper Advance
Java.lang - Runtime & ClassLoader Classes
java.lang - Class
Collection Framework Overview
Collections Interface
Collection Algorithms
Iterators
Locale & Random Classes
Observable & Timer Class
Restrictions On Generics
Wildcards
Recursion
Command Line Arguments
Inheritance - Abstract Class and Super
Try & Catch
Creating Exceptions
Generics
Generic Methods
Type Interface
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