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(); }}

None of these
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.
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.

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

will print Class Two method
Compilation Error
will print Class One method
compiles fine but print nothing
None of these

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

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

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JAVA Interfaces and Abstract Classes
Given the following piece of code:public interface Guard{ void doYourJob();}abstract public class Dog implements Guard{ }which of the following statements is correct?

This code will not compile, because class Dog must implement method doYourJob() from interface Guard.
This code will not compile, because method doYourJob() in interface Guard must be defined abstract.
This code will not compile, because in the declaration of class Dog we must use the keyword extends instead of implements.
This code will compile without any errors.

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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.

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