Quiz 5- OOAD (JAVA)

What is the output of the following Java program?

class A {

A() {

System.out.print("A");

}

}

class B extends A {

B() {

System.out.print("B");

}

}

public class Test {

public static void main(String[] args) {

B obj = new B();

}

}

• AB

• BA

• A

• B

What is the output of the following Java program?

class A {

void method() {

System.out.println("A");

}

}

class B extends A {

void method() {

System.out.println("B");

}

}

public class Test {

public static void main(String[] args) {

A obj1 = new B();

B obj2 = (B) obj1;

obj2.method();

}

}

• A

• B

• Compilation Error

• Runtime Error

What is the output of the following Java program?
class A {

static void staticMethod() {

System.out.println("A Static");

}

void instanceMethod() {

System.out.println("A Instance");

}

}

class B extends A {

static void staticMethod() {

System.out.println("B Static");

}

void instanceMethod() {

System.out.println("B Instance");

}

}

public class Test {

public static void main(String[] args) {

A aObj = new B();

B bObj = (B) aObj;

aObj.staticMethod();

bObj.instanceMethod();

}

}

• A Static
  B Instance

• B Static
  B Instance

• Compilation Error

• Runtime Error

What is the output of the following Java program?

interface MyInterface {

void myMethod();

}

class MyClass implements MyInterface {

public void myMethod() {

System.out.println("MyClass");

}

}

public class Test {

public static void main(String[] args) {

MyInterface obj = new MyClass() {

public void myMethod() {

System.out.println("Anonymous Inner Class");

}

};

obj.myMethod();

}

}

• MyClass

• MyInterface

• Anonymous Inner Class

• Compilation Error

What is the output of the following Java program?

class A {

final void show() {

System.out.println("A");

}

}

class B extends A {

void show() {

System.out.println("B");

}

}

public class Test {

public static void main(String[] args) {

A obj = new B();

obj.show();

}

}

• A

• B

• Compilation Error

• Runtime Error

What is the output of the following Java program?

public class Test {

public static void main(String[] args) {

String s1 = "Hello";

String s2 = new String("Hello");

System.out.println(s1 == s2);

System.out.println(s1.equals(s2));

}

}

• true

• false

• false

  true

• true

  false

What is the output of the following Java program?

public class Test {

public static void main(String[] args) {

String s1 = "Hello";

String s2 = "World";

String result = s1 + s2;

System.out.println(result == "HelloWorld"); // false

}

}

• true

• false

• Compilation error

• Runtime error

What is the output of the following Java program?

public class Test {

public static void main(String[] args) {

int x = 5;

int y = 10;

for (int i = 0; i < 3; i++) {

x += y;

y = y - 1;

}

System.out.println(x + " " + y);

}

}

• 32 7

• 34 8

• 35 8

• 45 7

What is the output of the following Java program?

public class Test {

public static void main(String[] args) {

StringBuffer sb1 = new StringBuffer("Hello");

StringBuffer sb2 = sb1;

sb1.append(" World");

System.out.println(sb2.toString());

}

}

• Hello

• Hello World

• World

• Compilation Error

What is the output of the following Java program?

public class Test {

public static void main(String[] args) {

int x = 5;

int y = 10;

int result = (x > 5) ? (x + y) : (x - y);

System.out.println(result);

}

}

• 5

• 15

• -5

• Compilation Error