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();}}

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

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

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

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JAVA Interfaces and Abstract Classes
What will be the output?1. public interface InfA{2. protected String getName();3. }public class Test implements InfA{ public String getName(){ return "test-name"; } public static void main (String[] args){ Test t = new Test(); System.out.println(t.getName()); }}

Compilation fails due to an error on lines 2
test-name
Compilation succeed but Runtime Exception
Compilation fails due to an error on lines 1
None of these

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JAVA Interfaces and Abstract Classes
Which of the following class definitions defines a legal abstract class?

class A { abstract void unfinished() { } }
class A { abstract void unfinished(); }
public class abstract A { abstract void unfinished(); }
abstract class A { abstract void unfinished(); }

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

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