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. }

null
Compilation fails due to an error on line 3
Compilation fails due to an error on line 8
A
None of these

ANSWER DOWNLOAD EXAMIANS APP

JAVA Interfaces and Abstract Classes
In Java, declaring a class abstract is useful

When it doesn't make sense to have objects of that class.
To force developers to extend the class not to use its capabilities.
When default implementations of some methods are not desirable.
When it makes sense to have objects of that class.
To prevent developers from further extending the class.

ANSWER DOWNLOAD EXAMIANS APP

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 keywords public and abstract cannot be used together.
Class School must be defined abstract.
You must add a return statement in method numberOfStudent().
The method numberOfStudent() in class School must have a body.

ANSWER DOWNLOAD EXAMIANS APP

JAVA Interfaces and Abstract Classes
What happens if the following program is compiled and executed?interface MyInterface{ void display();}interface MySubInterface extends MyInterface{ void display();}public class Test implements MySubInterface{ public void display(){ System.out.print("Welcome to Examveda."); } public static void main(String args[]){ Test t = new Test(); t.display(); }}

The code will lead to a compilation error as declaration of the display method has been provided in two interface.
The code will compile and execute successfully showing the output Welcome to Examians.
None of these
The code will lead to a compilation error due to public modifier while declaring the display method.
The code will lead to a compilation error as the display method is not declared as abstract.

ANSWER DOWNLOAD EXAMIANS APP
MORE MCQ ON JAVA Interfaces and Abstract Classes