Tata Infotech Previous Years Solved Sample Placement Papers

1. What is an interface in Java?

   A: A class

   B: A data type

   C: A blueprint for a class

   D: A data structure

   Ans: C

2. Which keyword is used to implement an interface?

   A: extends

   B: new

   C: interface

   D: implements

   Ans: D

3. Can an interface extend another interface in Java?

   A: No

   B: Yes

   Ans: B

4. Can an interface have a constructor?

   A: Yes

   B: No

   Ans: B

5. Which of the following access modifiers are implicitly applied to variables in an interface?

   A: private

   B: protected

   C: public

   D: default

   Ans: C

6. Is it possible to create an instance of an interface?

   A: Yes

   B: No

   Ans: B

7. How many interfaces can a Java class implement?

   A: None

   B: Only one

   C: Two

   D: As many as needed

   Ans: D

8. Can an interface inherit from a class?

   A: Yes

   B: No

   Ans: B

9. Can an interface method be declared as final?

   A: Yes

   B: No

   Ans: B

10. In Java 9, which type of methods can be added to interfaces to share code between methods?

    A: Static

    B: Private

    C: Final

    D: Protected

    Ans: B

11. An interface with no methods is known as?

    A: Abstract Interface

    B: Marker Interface

    C: Empty Interface

    D: Functional Interface

    Ans: B

12. Which keyword is used to define a default method in an interface?

    A: static

    B: default

    C: final

    D: abstract

    Ans: B

13. Are all methods in an interface abstract?

    A: Yes

    B: No

    Ans: B

14. Which of these can be contained in an interface?

    A: Abstract methods

    B: Constants

    C: Default and static methods

    D: All of the above

    Ans: D

15. Which Java feature helps achieve multiple inheritance?

    A: Abstract classes

    B: Static methods

    C: Interfaces

    D: Enums

    Ans: C

16. What is the default access modifier of a method in an interface in Java?

    A: private

    B: protected

    C: public

    D: None of the above

    Ans: C

17. Why were default methods introduced in Java 8 interfaces?

    A: To provide multiple inheritance

    B: To add utility functions

    C: To provide backward compatibility with older interface versions

    D: For better performance

    Ans: C

18. How do you access the fourth element of an array named numbers?

    A: numbers[4];

    B: numbers(3);

    C: numbers[3];

    D: numbers.get(3);

    Ans: C

19. Which of the following operators is used for concatenation of two strings?

    A: +

    B: *

    C: &

    D: +=

    Ans: A

20. Which of the following creates a mutable string?

    A: String

    B: StringBuilder

    C: StringChar

    D: StringMutable

    Ans: B

21. In Java, strings are:

    A: Primitive data types

    B: Immutable objects

    C: Mutable objects

    D: Arrays of characters

    Ans: B

22. How do you find the length of a string named 'example'?

    A: example.size()

    B: example.length()

    C: example.getLength()

    D: example.len()

    Ans: B

23. What is the result of the expression "Java" + "Programming"?

    A: JavaProgramming

    B: Java Programming

    C: Java-Programming

    D: JavaProgramming-

    Ans: A

24. Which method is used to compare two strings for equality?

    A: ==

    B: equals()

    C: compare()

    D: isEqual()

    Ans: B

25. Which class can create a string that is thread-safe?

    A: String

    B: StringBuffer

    C: StringBuilder

    D: StringSafe

    Ans: B

26. What is the root class for all Java classes?

    A: Object

    B: Class

    C: Superclass

    D: Root

    Ans: A

27. What is polymorphism?

    A: Multiple forms

    B: Single form

    C: No form

    D: Static form

    Ans: A