Given the following piece of code:public class School{ public abstract double numberOfStudent();}which of the following statements is true?

JAVA Interfaces and Abstract Classes
Given the following piece of code:public class School{ public abstract double numberOfStudent();}which of the following statements is true?

The method numberOfStudent() in class School must have a body.

Class School must be defined abstract.

You must add a return statement in method numberOfStudent().

The keywords public and abstract cannot be used together.

The method numberOfStudent() in class School must have a body.

Class School must be defined abstract.

You must add a return statement in method numberOfStudent().

The keywords public and abstract cannot be used together.

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JAVA Interfaces and Abstract Classes
interface Test{ int p = 10; //line 1 public int q = 20; //line 2 public static int r = 30; //line 3 public static final int s = 40; //line 4}Which of the above line will give compilation error?

4

1

None of these

3

2

4

1

None of these

3

2

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JAVA Interfaces and Abstract Classes
What will be the output when the following program is compiled and executed?abstract class TestAbstract{ String my_name; String myName(){ my_name = "Examveda"; return my_name; } abstract void display();}public class Test extends TestAbstract{ void display(){ String n = myName(); System.out.print("My name is "+ n); } public static void main(String args[]){ Test t = new Test(); t.display(); }}

Program compiles but leads to runtime exception.

None of these

Compilation error occurs as the abstract class TestAbstract contains a non-abstract method.

Program will compile and execute successfully and prints

Compilation error as class can not be declared as abstract.

Program compiles but leads to runtime exception.

None of these

Compilation error occurs as the abstract class TestAbstract contains a non-abstract method.

Program will compile and execute successfully and prints

Compilation error as class can not be declared as abstract.

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JAVA Interfaces and Abstract Classes
What is the output for the below code ?interface A{ public void printValue();}1. public class Test{2. public static void main (String[] args){3. A a1 = new A(){4. public void printValue(){5. System.out.println("A");6. }7. };8. a1.printValue();9. }10. }

A

None of these

Compilation fails due to an error on line 8

null

Compilation fails due to an error on line 3

A

None of these

Compilation fails due to an error on line 8

null

Compilation fails due to an error on line 3

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JAVA Interfaces and Abstract Classes
Which of the following statements regarding abstract classes are true?

An abstract class can be used as a data type.

All of these

An abstract class can be extended.

A subclass of a non-abstract superclass can be abstract.

A subclass can override a concrete method in a superclass to declare it abstract.

An abstract class can be used as a data type.

All of these

An abstract class can be extended.

A subclass of a non-abstract superclass can be abstract.

A subclass can override a concrete method in a superclass to declare it abstract.

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JAVA Interfaces and Abstract Classes
Suppose A is an abstract class, B is a concrete subclass of A, and both A and B have a default constructor. Which of the following is correct?1. A a = new A();2. A a = new B();3. B b = new A();4. B b = new B();

3 and 4

2 and 3

1 and 3

1 and 2

2 and 4

3 and 4

2 and 3

1 and 3

1 and 2

2 and 4

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JAVA Interfaces and Abstract Classes

JAVA Interfaces and Abstract Classes Given the following piece of code:public class School{ public abstract double numberOfStudent();}which of the following statements is true?

JAVA Interfaces and Abstract Classes interface Test{ int p = 10; //line 1 public int q = 20; //line 2 public static int r = 30; //line 3 public static final int s = 40; //line 4}Which of the above line will give compilation error?

JAVA Interfaces and Abstract Classes What is the output for the below code ?interface A{ public void printValue();}1. public class Test{2. public static void main (String[] args){3. A a1 = new A(){4. public void printValue(){5. System.out.println("A");6. }7. };8. a1.printValue();9. }10. }

JAVA Interfaces and Abstract Classes Which of the following statements regarding abstract classes are true?

JAVA Interfaces and Abstract Classes Suppose A is an abstract class, B is a concrete subclass of A, and both A and B have a default constructor. Which of the following is correct?1. A a = new A();2. A a = new B();3. B b = new A();4. B b = new B();

JAVA Interfaces and Abstract Classes
Given the following piece of code:public class School{ public abstract double numberOfStudent();}which of the following statements is true?

JAVA Interfaces and Abstract Classes
interface Test{ int p = 10; //line 1 public int q = 20; //line 2 public static int r = 30; //line 3 public static final int s = 40; //line 4}Which of the above line will give compilation error?

JAVA Interfaces and Abstract Classes
What is the output for the below code ?interface A{ public void printValue();}1. public class Test{2. public static void main (String[] args){3. A a1 = new A(){4. public void printValue(){5. System.out.println("A");6. }7. };8. a1.printValue();9. }10. }

JAVA Interfaces and Abstract Classes
Which of the following statements regarding abstract classes are true?

JAVA Interfaces and Abstract Classes
Suppose A is an abstract class, B is a concrete subclass of A, and both A and B have a default constructor. Which of the following is correct?1. A a = new A();2. A a = new B();3. B b = new A();4. B b = new B();