Java MCQ: Ultimate Trivia Quiz!

29 Questions | By Abhishekbs.1103 | Last updated: Mar 22, 2022 | Total Attempts: 560

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Questions and Answers

1.

What is the extension of byte code files?
- A.
  
  .java
- B.
  
  .class
- C.
  
  .xml
- D.
  
  .byte
2.

What is it called where a child object gets killed if the parent object is killed?
- A.
  
  Aggregation
- B.
  
  Composition
- C.
  
  Encapsulation
- D.
  
  Association
3.

What is true about constructors?
- A.
  
  It can contain return type
- B.
  
  It can take any number of parameters
- C.
  
  It can have any non access modifiers
- D.
  
  Constructor cannot throw an exception
4.

What would be the behavior if the constructor has a return type?
- A.
  
  Compilation error
- B.
  
  Runtime error
- C.
  
  Compilation and runs successfully
- D.
  
  Only String return type is allowed
5.

Which component is used to compile, debug, and execute the java program?
- A.
  
  JVM
- B.
  
  JDK
- C.
  
  JIT
- D.
  
  JRE
6.

Which component is responsible for converting bytecode into machine-specific code?
- A.
  
  JVM
- B.
  
  JDK
- C.
  
  JIT
- D.
  
  JRE
7.

What is the extension of java code files?
- A.
  
  .class
- B.
  
  .java
- C.
  
  .txt
- D.
  
  .js
8.

Which of these operators is used to allocate memory for an object?
- A.
  
  Malloc
- B.
  
  Alloc
- C.
  
  New
- D.
  
  give
9.

What will be the output of the following Java program? class box { int width; int height; int length; } class mainclass { public static void main(String args[]) { box obj1 = new box(); box obj2 = new box(); obj1.height = 1; obj1.length = 2; obj1.width = 1; obj2 = obj1; System.out.println(obj2.height); } }
- A.
  
  1
- B.
  
  2
- C.
  
  Runtime error
- D.
  
  Garbage value
10.

What will be the output of the following Java program? class box { int width; int height; int length; } class mainclass { public static void main(String args[]) { box obj = new box(); System.out.println(obj); } }
- A.
  
  0
- B.
  
  1
- C.
  
  Runtime error
- D.
  
  [email protected] in hexadecimal form
11.

Which of these keywords can be used to prevent Method overriding?
- A.
  
  Static
- B.
  
  constant
- C.
  
  Protected
- D.
  
  Final
12.

What will be the output of the following Java program? class A { int i; public void display() { System.out.println(i); } } class B extends A { int j; public void display() { System.out.println(j); } } class Dynamic_dispatch { public static void main(String args[]) { B obj2 = new B(); obj2.i = 1; obj2.j = 2; A r; r = obj2; r.display(); } }
- A.
  
  1
- B.
  
  2
- C.
  
  3
- D.
  
  4
13.

What is the return type of a method that does not return any value?
- A.
  
  Int
- B.
  
  Float
- C.
  
  void
- D.
  
  Double
14.

What will be the output of the following Java program? class box { int width; int height; int length; int volume; void volume(int height, int length, int width) { volume = width*height*length; } } class Prameterized_method { public static void main(String args[]) { box obj = new box(); obj.height = 1; obj.length = 5; obj.width = 5; obj.volume(3,2,1); System.out.println(obj.volume); } }
- A.
  
  0
- B.
  
  1
- C.
  
  6
- D.
  
  25
15.

What will be the output of the following Java program? class Output { static void main(String args[]) { int x , y = 1; x = 10; if(x != 10 && x / 0 == 0) System.out.println(y); else System.out.println(++y); } }
- A.
  
  1
- B.
  
  2
- C.
  
  Runtime Error
- D.
  
  Compilation Error
16.

Predict the output of following Java program? class Test { int i; } class Main { public static void main(String args[]) { Test t; System.out.println(t.i); }
- A.
  
  0
- B.
  
  Garbage value
- C.
  
  Compiler error
- D.
  
  runtime error
17.

Which of these keywords must be used to inherit a class?
- A.
  
  Super
- B.
  
  This
- C.
  
  Extent
- D.
  
  Extends
18.

What will be the output of the following Java program? class A { int i; void display() { System.out.println(i); } } class B extends A { int j; void display() { System.out.println(j); } } class inheritance_demo { public static void main(String args[]) { B obj = new B(); obj.i=1; obj.j=2; obj.display(); } }
- A.
  
  0
- B.
  
  1
- C.
  
  2
- D.
  
  Compilation Error
19.

All classes in Java are inherited from which class?
- A.
  
  Java.lang.class
- B.
  
  java.class.inherited
- C.
  
  Java.class.object
- D.
  
  Java.lang.Object
20.

In order to restrict a variable of a class from inheriting to subclass, how variable should be declared?
- A.
  
  Protected
- B.
  
  Private
- C.
  
  Public
- D.
  
  Static
21.

What will be the output of the following Java code? class test { int a; int b; void meth(int i , int j) { i *= 2; j /= 2; } } class Output { public static void main(String args[]) { test obj = new test(); int a = 10; int b = 20; obj.meth(a , b); System.out.println(a + " " + b); } }
- A.
  
  10 20
- B.
  
  20 10
- C.
  
  20 40
- D.
  
  40 20
22.

What will be the output of the following Java code? class overload { int x; int y; void add(int a) { x = a + 1; } void add(int a , int b) { x = a + 2; } } class Overload_methods { public static void main(String args[]) { overload obj = new overload(); int a = 0; obj.add(6, 7); System.out.println(obj.x); } }
- A.
  
  6
- B.
  
  7
- C.
  
  8
- D.
  
  9
23.

What is the extension of compiled java classes?
- A.
  
  .class
- B.
  
  .java
- C.
  
  .txt
- D.
  
  .js
24.

Which of these can be overloaded?
- A.
  
  Methods
- B.
  
  Constructors
- C.
  
  All of the mentioned
- D.
  
  None of the mentioned
25.

What is the data type of any class you write?
- A.
  
  Primitive
- B.
  
  Non primitive
- C.
  
  String
- D.
  
  None