Learn JAVA MCQs
Prepare JAVA MCQs (Multiple choice Questions) for exam and job interviews.
What is the output of System.out.println("5" + 3);?
1) 53
2) 8
3) Error
4) None of the above
Answer : 53
Which of the following statements about the `final` keyword is true?
1) Final variables can be reassigned.
2) Final methods cannot be overridden.
3) Final classes can be inherited.
4) None of the above
Answer : Final methods cannot be overridden.
What is the output of System.out.println(5 < 3);?
1) true
2) false
3) Error
4) None of the above
Answer : false
Which of the following is a valid declaration of a constructor in Java?
1) public ClassName() {}
2) ClassName() {}
3) public void ClassName() {}
4) None of the above
Answer : public ClassName() {}
What is the output of System.out.println(4 * 5 / 2);?
1) 10
2) 8
3) 20
4) None of the above
Answer : 10
Which of the following keywords is used to create a subclass in Java?
1) extends
2) inherits
3) implements
4) None of the above
Answer : extends
What is the output of System.out.println("123".charAt(0));?
1) 1
2) 2
3) 3
4) Error
Answer : 1
Which of the following is used to implement a thread-safe singleton class in Java?
1) synchronized
2) volatile
3) lazy initialization
4) All of the above
Answer : All of the above
What is the output of System.out.println(3 + 4 + "7");?
1) 77
2) 10
3) 34
4) None of the above
Answer : 77
Which of the following is true about `StringBuilder` in Java?
1) It is immutable.
2) It is synchronized.
3) It is mutable.
4) None of the above
Answer : It is mutable.