These Java Questions will help you to prepare the Java Section of the Mahindra placement Papers. If you have done BE/BTech from CS or IT, These type of questions you can get in your GET CS IT exam of Mahindra.
Question 1: What is the output of the following code?
class A {
int z;
static void func() {
System.out.println(z++);
}
public static void main(String args[]) {
func();
}
}A. 0
B. Junk value
C. Compilation error
D. Runtime error
Correct Answer: C. Compilation error
Explanation: The method func() is static and cannot access the instance variable z without an instance of the class A.
Question 2: What is the output of the following code?
public class Test {
public static void main(String[] args) {
int x = 3;
System.out.println(x++ + x);
}
}A. 6
B. 7
C. 8
D. Compilation error
Correct Answer: B. 7
Explanation: x++ uses 3 and increments x to 4. The expression becomes 3 + 4, which equals 7.
Question 3: What is the output of the following code?
public class Test {
public static void main(String[] args) {
String s = null;
System.out.println("Value: " + s);
}
}A. Value: null
B. Compilation error
C. Runtime error
D. Value:
Correct Answer: A. Value: null
Explanation: Concatenating a null string with another string results in the string "Value: null".
Question 4: What is the output of the following code?
public class Test {
public static void main(String[] args) {
int[] arr = {1, 2, 3};
System.out.println(arr[3]);
}
}A. 0
B. 3
C. Compilation error
D. Runtime error
Correct Answer: D. Runtime error
Explanation: Accessing arr[3] in an array of size 3 (indices 0 to 2) causes an ArrayIndexOutOfBoundsException.
Question 5: What is the output of the following code?
public class Test {
public static void main(String[] args) throws Exception {
String str1 = "hello";
String str2 = "hello";
System.out.println(str1 == str2);
}
}A. true
B. false
C. Compilation error
D. Runtime error
Correct Answer: A. true
Explanation: String literals are interned in Java, so str1 and str2 point to the same object in the string pool, making == return true.
Question 6: What is the output of the following code?
class Parent {
int x = 10;
}
public class Child extends Parent {
int x = 20;
public static void main(String[] args) {
Parent obj = new Child();
System.out.println(obj.x);
}
}A. 10
B. 20
C. Compilation error
D. Runtime error
Correct Answer: A. 10
Explanation: Variables are not polymorphic. The type of obj is Parent, so obj.x accesses Parent’s x, which is 10.
Question 7: What is the output of the following code?
public class Test implements Runnable {
public void run() {
System.out.println("Thread running");
}
public static void main(String[] args) {
Test t = new Test();
Thread th = new Thread(t);
th.run();
}
}A. Thread running
B. Nothing
C. Compilation error
D. Runtime error
Correct Answer: A. Thread running
Explanation: Calling th.run() directly executes the run() method in the main thread, printing Thread running. Note that th.start() would start a new thread, but run() does not.
Question 8: What is the output of the following code?
class A {
int x = 1;
}
public class Test extends A {
public static void main(String args[]) {
Test obj1 = new Test();
A obj2 = new A();
obj1 = (Test)obj2;
System.out.println(obj1.x);
}
}A. 1
B. Compilation error
C. Runtime error
D. None of the above
Correct Answer: C. Runtime error
Explanation: The downcast from A to Test causes a ClassCastException because obj2 is not an instance of Test.
Question 9: What is the output of the following code?
public class Test {
static int x;
static {
x = 5;
}
public static void main(String[] args) {
System.out.println(x);
}
}A. 0
B. 5
C. Compilation error
D. Runtime error
Correct Answer: B. 5
Explanation: The static block initializes x to 5 before the main method runs, so 5 is printed.
Question 10: What is the output of the following code?
public class Test {
public static void main(String[] args) {
try {
int x = Integer.parseInt("abc");
} catch (NumberFormatException e) {
System.out.println("Number error");
} catch (Exception e) {
System.out.println("General error");
}
}
}A. Number error
B. General error
C. Compilation error
D. Runtime error
Correct Answer: A. Number error
Explanation: Integer.parseInt("abc") throws a NumberFormatException, which is caught by the first catch block, printing Number error.