1. Which of the following is the correct way to declare a constant in Java?
a) const int x = 5;
b) final int x = 5;
c) static final x = 5;
d) int final x = 5;
Answer: b) final int x = 5;
2. Which operator is used to concatenate strings in Java?
a) +
b) &
c) *
d) .
Answer: a) +
3. What is the default value of an object reference variable in Java?
a) null
b) 0
c) ""
d) undefined
Answer: a) null
4. Which method is used to get the length of an array in Java?
a) length()
b) getLength()
c) size()
d) length
Answer: d) length
5. Which keyword is used to prevent a method from being overridden in Java?
a) static
b) final
c) private
d) protected
Answer: b) final
6. What is the output of the following Java code: System.out.println(3 + 4 + "Java");?
a) 7Java
b) Java7
c) 34Java
d) Java34
Answer: a) 7Java
7. Which of the following is the correct way to declare an array of integers in Java?
a) int[] arr;
b) int arr[];
c) int[] arr = new int[10];
d) All of the above
Answer: d) All of the above
8. Which of the following is used to define a package in Java?
a) package;
b) import;
c) namespace;
d) package packageName;
Answer: d) package packageName;
9. Which of these methods is used to read a line of text from the console in Java?
a) Scanner.readLine()
b) Console.read()
c) BufferedReader.readLine()
d) System.in.read()
Answer: c) BufferedReader.readLine()
10. What does the this keyword refer to in Java?
a) The parent class
b) The current object
c) A static method
d) A new instance of a class
Answer: b) The current object
11. Which of these methods is used to get the value of a string in Java?
a) getString()
b) valueOf()
c) toString()
d) getValue()
Answer: b) valueOf()
12. Which of these is the correct way to handle exceptions in Java?
a) try-catch-finally
b) try-catch
c) catch-throw
d) throw-try
Answer: a) try-catch-finally
13. Which of these is used to create a thread in Java?
a) Thread.run()
b) Thread.start()
c) Thread.create()
d) Thread.invoke()
Answer: b) Thread.start()
14. What is the output of the following Java code: System.out.println(10 / 3);?
a) 3
b) 3.0
c) 3.3333
d) Error
Answer: a) 3
15. Which of the following is true about the String class in Java?
a) Strings are mutable
b) Strings are immutable
c) Strings can only be created using the new keyword
d) Strings cannot be concatenated
Answer: b) Strings are immutable
0 Comments