Interview Questions

1. 1. program on same method call using different operation? class one { int one(int x){ return xx;} } class two extends one { int one(int x) { return xxx; } } class { two ref=new one(); ref.one(5); }

Options:

a. Incompatible types

b. 25

c. 125

d. 25 125

Reveal Answer

2. 2. Write a program to pass the values as arguments and accepting it. class A { final int res(int a, int b) { System.out.println(a+""+b); return 0; } class B extends A { int res(int a, int b){ System.out.println(a+""+b); return 1; } class Test { public static void main(String args[]) { B b=new B(); } System.out.print(b.res(1,2)); }

Options:

a. compile error

b. 1 2

c. 1

d. 2

Reveal Answer

3. 3.Write a program on inheritance and check weather the given object is instance of a class or not? class A{ } class B extends A{ } class C extends A{ } class X { A a1=new B(); if(a1 instanceof B) System.out.println(“I'm Class B”); else if(a1 instanceof A) System.out.println(“I'm Class A”); else if(a1 instanceof C) System.out.println(“I'm Class C”); else System.out.print(“no match”);

Options:

a. I'm Class A

b. I'm Class B

c. I'm Class C

d. no match

Reveal Answer

4. 4.write a program on inheritance where by creating an object and initialize data in it ? Class Test{ final int res(int a, int b) { return 0; } } Class Test1 extends Test { final int res(int a, int b) { return 1; } } Class x{ Test1 tes=new Test1(); System.out.println(tes.res(0,1)); }

Options:

a. 0

b. 1

c. compile error

d. exception

Reveal Answer

5. 5.write a program on inheritance and access the sub class from the super class. class A { A(int x){ } class B extends A{ } class Test{ public static void main(String args[]){ A a= new B(); System.out.print(“completed”); } }

Options:

a. completed

b. compile error

c. exception

d. displays empty

Reveal Answer

6. 6.write a program to accept the string by using constructor with similar parameters. class x { int i=0; public x(String s) { i=1; } class y extends x { public y(String s) { i=2; } public static void main(String args[]) { y z=new y(“hello”); System.out.println(y.i); } }

Options:

a. 0

b. 1

c. 2

d. compiler error

Reveal Answer

7. 7. Which of these keyword must be used to inherit a class?

Options:

a. super

b. this

c. extent

d. extends

Reveal Answer

8. 8. Which of these keywords is used to refer to member of base class from a sub class?

Options:

a. upper

b. super

c. this

d. None of the mentioned

Reveal Answer

9. 8. Which of these keywords is used to refer to member of base class from a sub class?

Options:

a. upper

b. super

c. this

d. None of the mentioned

Reveal Answer

10. 9. A class member declared protected becomes member of subclass of which type?

Options:

a. public member

b. private member

c. protected member

d. static member

Reveal Answer

11. 10. What is the output of this 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(); } }

Options:

a. 0

b. 1

c. 2

d. Compilation Error

Reveal Answer

12. 11.What is the output of this program? class A { int i; } class B extends A { int j; void display() { super.i = j + 1; System.out.println(j + " " + i); } } class inheritance { public static void main(String args[]) { B obj = new B(); obj.i=1; obj.j=2; obj.display(); } }

Options:

a. 2 2

b. 3 3

c. 2 3

d. 3 2

Reveal Answer

13. 12.What is the output of this program? class A { public int i; private int j; } class B extends A { void display() { super.j = super.i + 1; System.out.println(super.i + " " + super.j); } } class inheritance { public static void main(String args[]) { B obj = new B(); obj.i=1; obj.j=2; obj.display(); } }

Options:

a. 2 2

b. 3 3

c. Runtime Error

d. Compilation Error

Reveal Answer

14. 13.What is the output of this program? class A { public int i; public int j; A() { i = 1; j = 2; } } class B extends A { int a; B() { super(); } } class super_use { public static void main(String args[]) { B obj = new B(); System.out.println(obj.i + " " + obj.j) } }

Options:

a. 1 2

b. 2 1

c. Runtime Error

d. Compilation Error

Reveal Answer

15. 14. What is the output of this program? class A { public int i; protected int j; } class B extends A { int j; void display() { super.j = 3; System.out.println(i + " " + j); } } class Output { public static void main(String args[]) { B obj = new B(); obj.i=1; obj.j=2; obj.display(); } }

Options:

a. 1 2

b. 2 1

c. 1 3

d. 3 1

Reveal Answer

16. 15.What is the result of compiling and running the following code? class Base { public Base() { System.out.print("Base"); } } public class Derived extends Base{ public Derived() { this("Examveda"); System.out.print("Derived"); } public Derived(String s){ System.out.print(s); } public static void main(String[] args){ new Derived(); } }

Options:

a. ExamvedaDerived

b. ExamvedaBaseDerived

c. BaseExamvedaDerived

d. ExamvedaDerivedBase

e. Compilation Error

Reveal Answer

17. 16.What is the output of the following program code? abstract class C1 { public C1(){ System.out.print(1); } } class C2 extends C1 { public C2() { System.out.print(2); } } class C3 extends C2{ public C3() { System.out.println(3); } } public class Test{ public static void main(String[] a){ new C3(); } }

Options:

a. 12

b. 23

c. 123

d. 321

Reveal Answer

18. 17.What will be the output? interface A { public void method1(); } class One implements A { public void method1() { System.out.println("Class One method1"); } } class Two extends One { public void method1() { System.out.println("Class Two method1"); } } public class Test extends Two { public static void main(String[] args) { A a = new Two(); a.method1(); } }

Options:

a. Compilation Error

b. Class One method1

c. Class Two method1

d. Throws a NoSuchMethodException at runtime.

e. E.None of these

Reveal Answer

19. 18.What is the result of compiling and running this program? class Mammal { void eat(Mammal m) { System.out.println("Mammal eats food"); } } class Cattle extends Mammal{ void eat(Cattle c) { System.out.println("Cattle eats hay"); } } class Horse extends Cattle { void eat(Horse h) { System.out.println("Horse eats hay"); } } public class Test { public static void main(String[] args){ Mammal h = new Horse(); Cattle c = new Horse(); c.eat(h); } }

Options:

a. prints "Mammal eats food"

b. prints "Cattle eats hay"

c. prints "Horse eats hay"

d. Class cast Exception at runtime.

e. None of these

Reveal Answer

20. 19.Determine the output: class A { public void method1() { System.out.print("Class A method1"); } } class B extends A { public void method2() { System.out.print("Class B method2"); } } class C extends B { public void method2() { System.out.print("Class C method2"); } public void method3() { System.out.print("Class C method3"); } } public class Test { public static void main(String args[]) { A a = new A(); C c = new C(); c.method2(); a = c; a.method3(); } }

Options:

a. Class B method2 Class C method3

b. Class C method2 Class C method3

c. Compilation Error

d. Runtime exception

e. None of these

Reveal Answer

21. 20.What Will be printed after executing following program code class Base { int value = 0; Base() { addValue(); } void addValue(){ value += 10; } int getValue() { return value; } } class Derived extends Base { Derived() { addValue(); } void addValue() { value += 20; } } public class Test { public static void main(String[] args) { Base b = new Derived(); System.out.println(b.getValue()); } }

Options:

a. 30

b. 10

c. 40

d. 20

e. None of these

Reveal Answer

22. 21.What will be the output? class Parent { public void method() { System.out.println("Hi i am parent"); } } public class Child extends Parent { protected void method(){ System.out.println("Hi i am Child"); } public static void main(String args[]){ Child child = new Child(); child.method(); } }

Options:

a. Compiles successfully and print

b. Compiles successfully and print

c. Compile time error

d. Run Time error

e. None of This

Reveal Answer

23. 22.What will be the output? class One { final int a = 15; } class Two extends One { final int a = 20; } public class Test extends Two { final int a = 30; public static void main(String args[]){ Test t = new One(); System.out.print(t.a); } }

Options:

a. 15

b. 20

c. 30

d. Compiler Error

e. None of these

Reveal Answer

24. 23.What will be the output? class A { int i = 10; public void printValue(){ System.out.print("Value-A"); } } class B extends A { int i = 12; public void printValue(){ System.out.print("Value-B"); } } public class Test { public static void main(String args[]){ A a = new B(); a.printValue(); System.out.print(a.i); } } }

Options:

a. Value-B 11

b. Value-B 10

c. Value-A 10

d. Value-A 11

e. None of these

Reveal Answer

25. 24.What will be the result after compiling this code? class SuperClass { public int doIt(String str, Integer... data)throws Exception{ String signature = "(String, Integer[])"; System.out.println(str + " " + signature); return 1; } } public class Test extends SuperClass { public int doIt(String str, Integer... data){ String signature = "(String, Integer[])"; System.out.println("Overridden: " + str + " " +signature); return 0; } public static void main(String... args){ SuperClass sb = new Test(); sb.doIt("hello", 3); } }

Options:

a. Overridden: hello (String, Integer[])

b. hello (String, Integer[])

c. Compilation fails

d. None of these

Reveal Answer

26. 25.what will bet he output of the following code? class A { A(String s) { } A() { } } class B extends A { B() { } B(String s) { super(s); } void test() { // insert code here } } Which of the below code can be insert at line 7 to make clean compilation ?

Options:

a. A a =new B();

b. A a = new B(5);

c. A a = new A(String s);

d. All of the above

e. None of these

Reveal Answer

27. 26.Determine output: class A { public void printValue(){ System.out.println("Value-A"); } } class B extends A { public void printNameB(){ System.out.println("Name-B"); } } class C extends A { public void printNameC(){ System.out.println("Name-C"); } } public class Test{ public static void main (String[] args){ B b = new B(); C c = new C(); newPrint(b); newPrint(c); } public static void newPrint(A a){ a.printValue(); } }

Options:

a. Value-A Name-B

b. Value-A Value-A

c. Value-A Name-C

d. Name-B Name-C

e. None of these

Reveal Answer

28. 27.Determine output: class A { public void printName(){ System.out.println("Name-A"); } } class B extends A{ public void printName(){ System.out.println("Name-B"); } } class C extends A { public void printName() { System.out.println("Name-C"); } } public class Test { public static void main (String[] args){ B b = new B(); C c = new C(); b = c; newPrint(b); } public static void newPrint(A a){ a.printName(); } }

Options:

a. Name B

b. Name C

c. Compilation fails due to an error on lines 5

d. Compilation fails due to an error on lines 9

e. None of these

Reveal Answer

29. 28.What is the output for the below code ? class A { private void printName() { System.out.println("Value-A"); } } class B extends A{ public void printName() { System.out.println("Name-B"); } } public class Test { public static void main (String[] args){ B b = new B(); b.printName(); } }

Options:

a. Value-A

b. Name-B

c. Value-A Name-B

d. Compilation fails - private methods can't be override

e. None of these

Reveal Answer

30. 29.What will be the result of compiling and running the given code? class A { int b=10; private A() { this.b=7; } int f() { return b; } } class B extends A { int b; } public class Test { public static void main(String[] args){ A a = new B(); System.out.println(a.f()); } }

Options:

a. Compilation Fails

b. Prints 0

c. Prints 10

d. None of these

Reveal Answer

31. 29.What will be the result of compiling and running the given code? class A { int b=10; private A() { this.b=7; } int f() { return b; } } class B extends A { int b; } public class Test { public static void main(String[] args){ A a = new B(); System.out.println(a.f()); } }

Options:

a. Compilation Fails

b. Prints 0

c. Prints 10

d. Prints 7

e. None of these

Reveal Answer

32. 30.What will be the result of compiling and executing the following program code? class Vehicle { public void printSound() { System.out.print("vehicle"); } } class Car extends Vehicle { public void printSound() { System.out.print("car"); } } class Bike extends Vehicle { public void printSound(){ System.out.print("bike"); } } public class Test { public static void main(String[] args){ Vehicle v = new Car(); Bike b = (Bike) v; v.printSound(); b.printSound(); } }

Options:

a. Compilation fails.

b. ClassCastException exception is thrown at runtime.

c. "vehiclecar" is printed.

d. "vehiclebike" is printed.

e. "carcar" is printed.

Reveal Answer

33. 31.Dermine output: class Small { public Small(){ System.out.print("a "); } } class Small2 extends Small { public Small2(){ System.out.print("b "); } } class Small3 extends Small2 { public Small3() { System.out.print("c "); } } public class Test { public static void main(String args[]){ new Small3(); } }

Options:

a. a

b. c

c. a b c

d. c b a

e. The code runs without output..

Reveal Answer

Interview Questions and Answer

1. 1. program on same method call using different operation? class one { int one(int x){ return xx;} } class two extends one { int one(int x) { return xxx; } } class { two ref=new one(); ref.one(5); }

4. 4.write a program on inheritance where by creating an object and initialize data in it ? Class Test{ final int res(int a, int b) { return 0; } } Class Test1 extends Test { final int res(int a, int b) { return 1; } } Class x{ Test1 tes=new Test1(); System.out.println(tes.res(0,1)); }

5. 5.write a program on inheritance and access the sub class from the super class. class A { A(int x){ } class B extends A{ } class Test{ public static void main(String args[]){ A a= new B(); System.out.print(“completed”); } }

6. 6.write a program to accept the string by using constructor with similar parameters. class x { int i=0; public x(String s) { i=1; } class y extends x { public y(String s) { i=2; } public static void main(String args[]) { y z=new y(“hello”); System.out.println(y.i); } }

7. 7. Which of these keyword must be used to inherit a class?

8. 8. Which of these keywords is used to refer to member of base class from a sub class?

9. 8. Which of these keywords is used to refer to member of base class from a sub class?

10. 9. A class member declared protected becomes member of subclass of which type?

11. 10. What is the output of this 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(); } }

12. 11.What is the output of this program? class A { int i; } class B extends A { int j; void display() { super.i = j + 1; System.out.println(j + " " + i); } } class inheritance { public static void main(String args[]) { B obj = new B(); obj.i=1; obj.j=2; obj.display(); } }

14. 13.What is the output of this program? class A { public int i; public int j; A() { i = 1; j = 2; } } class B extends A { int a; B() { super(); } } class super_use { public static void main(String args[]) { B obj = new B(); System.out.println(obj.i + " " + obj.j) } }

15. 14. What is the output of this program? class A { public int i; protected int j; } class B extends A { int j; void display() { super.j = 3; System.out.println(i + " " + j); } } class Output { public static void main(String args[]) { B obj = new B(); obj.i=1; obj.j=2; obj.display(); } }

22. 21.What will be the output? class Parent { public void method() { System.out.println("Hi i am parent"); } } public class Child extends Parent { protected void method(){ System.out.println("Hi i am Child"); } public static void main(String args[]){ Child child = new Child(); child.method(); } }

23. 22.What will be the output? class One { final int a = 15; } class Two extends One { final int a = 20; } public class Test extends Two { final int a = 30; public static void main(String args[]){ Test t = new One(); System.out.print(t.a); } }

26. 25.what will bet he output of the following code? class A { A(String s) { } A() { } } class B extends A { B() { } B(String s) { super(s); } void test() { // insert code here } } Which of the below code can be insert at line 7 to make clean compilation ?

29. 28.What is the output for the below code ? class A { private void printName() { System.out.println("Value-A"); } } class B extends A{ public void printName() { System.out.println("Name-B"); } } public class Test { public static void main (String[] args){ B b = new B(); b.printName(); } }

30. 29.What will be the result of compiling and running the given code? class A { int b=10; private A() { this.b=7; } int f() { return b; } } class B extends A { int b; } public class Test { public static void main(String[] args){ A a = new B(); System.out.println(a.f()); } }

31. 29.What will be the result of compiling and running the given code? class A { int b=10; private A() { this.b=7; } int f() { return b; } } class B extends A { int b; } public class Test { public static void main(String[] args){ A a = new B(); System.out.println(a.f()); } }

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