Objective type Question Answer
Class – X , ICSE
Prepared & Guided By : Souvik Chakraborty , M.Sc(C.S) , B.Ed
1. Basics
Q1.
Assertion (A): Java is platform-independent.
Reason (R): Java code is compiled to bytecode, which can run on any platform
with a JVM.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q2.
Assertion (A): Java supports multiple inheritance using classes.
Reason (R): Java provides interfaces to achieve multiple inheritance.
Answer:
A is false, R is true.
(Explanation: Java does not support multiple inheritance with classes
directly, but it can be achieved through interfaces.)
Q3.
Assertion (A): Java uses garbage collection to manage memory.
Reason (R): The System.gc() method guarantees the execution of the garbage
collector.
Answer:
By : Souvik_Chakraborty_M.Sc_CS 1/17
A is true, R is false.
(Explanation: The System.gc() method only suggests the JVM to run the
garbage collector; it does not guarantee it.)
Q4.
Assertion (A): Java does not support operator overloading.
Reason (R): Java’s simplicity is maintained by restricting operator overloading.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q5.
Assertion (A): Java’s main() method must be declared public.
Reason (R): The main() method is the entry point for the JVM to start program
execution.
Answer:
A is true, R is true, and R is the correct explanation of A.
2. Loops
Q1.
Assertion (A): The while loop is an entry-controlled loop.
Reason (R): The condition is checked before the loop body is executed in a while
loop.
Answer:
A is true, R is true, and R is the correct explanation of A.
By : Souvik_Chakraborty_M.Sc_CS 2/17
Q2.
Assertion (A): The for loop is useful for iterating over an array.
Reason (R): The for loop can have an initialization, condition, and
increment/decrement in a single line.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q3.
Assertion (A): A break statement terminates the nearest enclosing loop.
Reason (R): The break statement stops loop execution and transfers control to the
statement after the loop.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q4.
Assertion (A): The continue statement in a loop skips the current iteration.
Reason (R): The continue statement transfers control to the beginning of the loop.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q5.
Assertion (A): A do-while loop checks the condition at the start of the loop.
Reason (R): A do-while loop is suitable for executing the body at least once
regardless of the condition.
Answer:
By : Souvik_Chakraborty_M.Sc_CS 3/17
A is false, R is true.
(Explanation: The condition in a do-while loop is checked after the loop
body runs.)
3. Arrays
Q1.
Assertion (A): The elements of an array are stored in contiguous memory
locations.
Reason (R): Accessing elements of an array using indices ensures fast retrieval.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q2.
Assertion (A): The length of an array can be changed after its declaration.
Reason (R): Arrays in Java are fixed in size once created.
Answer:
A is false, R is true.
(Explanation: Arrays in Java have a fixed size, and their length cannot be
modified after declaration.)
Q3.
Assertion (A): The ArrayIndexOutOfBoundsException is thrown if an invalid
index is accessed.
Reason (R): Java checks array bounds at runtime to ensure memory safety.
Answer:
A is true, R is true, and R is the correct explanation of A.
By : Souvik_Chakraborty_M.Sc_CS 4/17
Q4.
Assertion (A): Arrays can store both primitive types and objects in Java.
Reason (R): Arrays are a part of Java’s collection framework.
Answer:
A is true, R is false.
(Explanation: Arrays are not a part of the Java collection framework; they
are part of the core language.)
Q5.
Assertion (A): An array can be passed as an argument to a method.
Reason (R): Passing an array to a method sends a reference to the original array.
Answer:
A is true, R is true, and R is the correct explanation of A.
4. Strings
Q1.
Assertion (A): Strings in Java are stored in the heap memory.
Reason (R): The String class is immutable, and string literals are stored in the
string pool.
Answer:
A is true, R is true, but R is not the correct explanation of A.
By : Souvik_Chakraborty_M.Sc_CS 5/17
Q2.
Assertion (A): The == operator checks the reference equality of strings.
Reason (R): The equals() method in Java checks the content equality of strings.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q3.
Assertion (A): The StringBuilder class is preferred for string concatenation in a
loop.
Reason (R): The StringBuilder class is mutable and avoids creating multiple
objects.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q4.
Assertion (A): The substring() method in Java returns a new string.
Reason (R): The String class in Java creates new objects for string manipulation.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q5.
Assertion (A): Strings are a primitive data type in Java.
Reason (R): Java provides wrapper classes for primitive data types.
Answer:
By : Souvik_Chakraborty_M.Sc_CS 6/17
A is false, R is true.
(Explanation: Strings are not primitive; they are objects of the String
class.)
5. Methods
Q1.
Assertion (A): A method in Java can have multiple return statements.
Reason (R): The control of a method returns to the calling function after a return
statement.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q2.
Assertion (A): Methods can have the same name in Java.
Reason (R): Method overloading allows defining methods with the same name but
different parameter lists.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q3.
Assertion (A): A method declared as static can be called without creating an
object.
Reason (R): Static methods belong to the class, not an instance of the class.
Answer:
A is true, R is true, and R is the correct explanation of A.
By : Souvik_Chakraborty_M.Sc_CS 7/17
Q4.
Assertion (A): A method can be recursive in Java.
Reason (R): Recursive methods call themselves to solve smaller sub-problems.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q5.
Assertion (A): Methods can only return void in Java.
Reason (R): The return type of a method defines what type of value it returns.
Answer:
A is false, R is true.
(Explanation: Methods can return various data types, not just void.)
6. Constructors
Q1.
Assertion (A): Constructors do not have a return type.
Reason (R): Constructors are used for object initialization, not for returning
values.
Answer:
A is true, R is true, and R is the correct explanation of A.
By : Souvik_Chakraborty_M.Sc_CS 8/17
Q2.
Assertion (A): If no constructor is defined in a class, Java provides a default
constructor.
Reason (R): The default constructor initializes object fields with default values.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q3.
Assertion (A): Constructors can be overloaded.
Reason (R): Constructor overloading allows creating multiple constructors with
different parameters.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q4.
Assertion (A): A constructor can be static.
Reason (R): Constructors are special methods called when an object is created,
and static methods can be accessed without an instance.
Answer:
A is false, R is false.
(Explanation: Constructors cannot be static.)
Q5.
Assertion (A): Constructors cannot be inherited.
Reason (R): Constructors are not methods and are only called during the
instantiation of an object.
By : Souvik_Chakraborty_M.Sc_CS 9/17
Answer:
A is true, R is true, and R is the correct explanation of A.
7. Method Overloading
Q1.
Assertion (A): Method overloading allows multiple methods with the same name
in a class.
Reason (R): The methods must differ in their parameter type, number, or order.
Answer:
A is true, R is true, and R is the correct explanation of A.
Q2.
Assertion (A): The return type of overloaded methods must be different.
Reason (R): The Java compiler uses return type to differentiate overloaded
methods.
Answer:
A is false, R is false.
(Explanation: Overloaded methods cannot be differentiated by return type
alone.)
Q3.
Assertion (A): Method overloading improves code readability.
Reason (R): Similar methods can be grouped under the same name with different
parameters.
Answer:
By : Souvik_Chakraborty_M.Sc_CS 10/17
A is true, R is true, and R is the correct explanation of A.
Q4.
Assertion (A): Method overloading can only be done within the same class.
Reason (R): Method overriding is used to redefine methods in subclasses.
Answer:
A is true, R is true, but R is not the correct explanation of A.
(Explanation: Method overloading can indeed only be done within the same
class.)
Q5.
Assertion (A): An overloaded method can have a static modifier.
Reason (R): Method overloading can be applied to both static and instance
methods.
Answer:
A is true, R is true, and R is the correct explanation of A.
1. Arrays
Q1.
class ArrayExample {
public static void main(String[] args) {
int[] arr = {10, 20, 30, 40, 50};
int i = 1, j = 3, sum = 0;
sum += arr[i++] + arr[--j];
sum += arr[i]++ + arr[j--];
sum += arr[++i] + arr[j];
By : Souvik_Chakraborty_M.Sc_CS 11/17
System.out.println("Sum: " + sum);
}
}
Output:
Sum: 145
Explanation:
1. arr[i++] + arr[--j]: i = 1, so arr[i++] = 20; --j = 2, so arr[2] = 30.
Sum becomes 20 + 30 = 50.
o Now i = 2, j = 2.
2. arr[i]++ + arr[j--]: arr[2]++ = 30 (post-increment) and arr[2] = 30.
Sum becomes 50 + 30 + 30 = 110.
o Now i = 2, j = 1.
3. arr[++i] + arr[j]: ++i = 3, so arr[3] = 40; arr[1] = 20. Sum becomes
110 + 40 + 20 = 145.
Q2.
class ArrayManipulation {
public static void main(String[] args) {
int[] a = {5, 10, 15, 20, 25};
int x = 0, y = 4, diff = 0;
diff = a[y--] - a[++x];
diff += a[x++] + a[--y];
diff -= a[y--] - a[--x];
System.out.println("Difference: " + diff);
}
}
Output:
Difference: 15
Explanation:
1. a[y--] - a[++x]: a[4] = 25, ++x = 1, so a[1] = 10. Difference becomes
25 - 10 = 15.
o Now y = 3, x = 1.
By : Souvik_Chakraborty_M.Sc_CS 12/17
2. a[x++] + a[--y]: a[1] = 10 (post-increment), --y = 2, so a[2] = 15.
Difference becomes 15 + 10 + 15 = 40.
o Now x = 2, y = 2.
3. a[y--] - a[--x]: a[2] = 15, --x = 1, so a[1] = 10. Difference becomes
40 - (15 - 10) = 15.
Q3.
class ArrayRotation {
public static void main(String[] args) {
int[] arr = {1, 2, 3, 4, 5};
int n = arr.length;
for (int i = 0; i < n; i++) {
int temp = arr[0];
for (int j = 0; j < n - 1; j++) {
arr[j] = arr[j + 1];
}
arr[n - 1] = temp;
// Printing the array after each rotation
for (int k = 0; k < n; k++) {
System.out.print(arr[k] + " ");
}
System.out.println();
}
}
}
Output:
Copy code
2 3 4 5 1
3 4 5 1 2
4 5 1 2 3
5 1 2 3 4
1 2 3 4 5
Explanation: The program performs a left rotation on the array for n iterations.
Each iteration moves the first element to the end while shifting all others to the
left.
By : Souvik_Chakraborty_M.Sc_CS 13/17
Q4.
class ArraySum {
public static void main(String[] args) {
int[][] arr = {
{1, 2, 3},
{4, 5, 6},
{7, 8, 9}
};
int rowSum = 0, colSum = 0;
for (int i = 0; i < arr.length; i++) {
rowSum += arr[i][i];
colSum += arr[i][arr.length - i - 1];
}
System.out.println("Diagonal 1 Sum: " + rowSum);
System.out.println("Diagonal 2 Sum: " + colSum);
}
}
Output:
Diagonal 1 Sum: 15
Diagonal 2 Sum: 15
Explanation:
Diagonal 1: 1 + 5 + 9 = 15
Diagonal 2: 3 + 5 + 7 = 15.
2. Strings
Q1.
class StringExample {
public static void main(String[] args) {
String s = "ICSE";
s = s.concat(" 2024").toLowerCase();
s = s.substring(0, 6);
StringBuilder sb = new StringBuilder(s);
sb.reverse();
s = sb.toString();
System.out.println(s);
By : Souvik_Chakraborty_M.Sc_CS 14/17
}
}
Output:
420 202
Explanation:
1. s.concat(" 2024") → ICSE 2024.
2. .toLowerCase() → icse 2024.
3. .substring(0, 6) → icse 2.
4. StringBuilder.reverse() → 420 202.
Q2.
class PalindromeCheck {
public static void main(String[] args) {
String str = "MADAM";
String rev = "";
for (int i = str.length() - 1; i >= 0; i--) {
rev += str.charAt(i);
}
if (str.equals(rev)) {
System.out.println("Palindrome");
} else {
System.out.println("Not a Palindrome");
}
}
}
Output:
Palindrome
Explanation: The input string MADAM matches its reverse, so it is a palindrome.
Q3.
class SubstringCount {
public static void main(String[] args) {
String s = "ICSE ICSE ICSE";
By : Souvik_Chakraborty_M.Sc_CS 15/17
String word = "ICSE";
int count = 0;
for (int i = 0; i <= s.length() - word.length(); i++) {
if (s.substring(i, i + word.length()).equals(word)) {
count++;
}
}
System.out.println("Count: " + count);
}
}
Output:
Count: 3
Explanation: The program iterates over the string and counts non-overlapping
occurrences of "ICSE".
Q4.
class ReplaceVowels {
public static void main(String[] args) {
String s = "ICSE 2024";
String result = "";
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
if ("AEIOUaeiou".indexOf(c) != -1) {
result += '*';
} else {
result += c;
}
}
System.out.println(result);
}
}
Output:
*CS* 2024
Explanation:
The vowels (I, E) are replaced with *.
By : Souvik_Chakraborty_M.Sc_CS 16/17
Q5.
class AnagramCheck {
public static void main(String[] args) {
String str1 = "listen";
String str2 = "silent";
char[] arr1 = str1.toCharArray();
char[] arr2 = str2.toCharArray();
java.util.Arrays.sort(arr1);
java.util.Arrays.sort(arr2);
if (java.util.Arrays.equals(arr1, arr2)) {
System.out.println("Anagrams");
} else {
System.out.println("Not Anagrams");
}
}
}
Output:
Anagrams
Explanation:
Sorting the characters of both strings and comparing them shows that they are
anagrams.
XXXXX END XXXXX
Best Wish For your Pre-Board Examination
By : Souvik_Chakraborty_M.Sc_CS 17/17
