JAVA Interfaces and Abstract Classes
Which two of the following are legal declarations for abstract classes and interfaces?1. final abstract class Test {}2. public static interface Test {}3. final public class Test {}4. protected abstract class Test {}5. protected interface Test {}6. abstract public class Test {}

2 and 4
5 and 6
3 and 5
1 and 2
3 and 6

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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?

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

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

When it makes sense to have objects of that class.
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.
To prevent developers from further extending the class.

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

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