Determine output of the following code.
interface A { }
class C { }
class D extends C { }
class B extends D implements A { }
public class Test extends Thread{
public static void main(String[] args){
B b = new B();
if (b instanceof A)
System.out.println("b is an instance of A");
if (b instanceof C)
System.out.println("b is an instance of C");
}
}
interface A { }
class C { }
class D extends C { }
class B extends D implements A { }
public class Test extends Thread{
public static void main(String[] args){
B b = new B();
if (b instanceof A)
System.out.println("b is an instance of A");
if (b instanceof C)
System.out.println("b is an instance of C");
}
}A. Nothing.
B. b is an instance of A.
C. b is an instance of C.
D. b is an instance of A followed by b is an instance of C.
Answer: Option D
This Question Belongs to Java Program >> Interfaces And Abstract Classes
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Comments ( 1 )
A. A contract specifying a set of methods that a class must implement
B. A class that cannot be instantiated
C. A class that contains only static methods
D. A subclass of the Object class
In Java, can a class implement multiple interfaces?
A. Interfaces cannot be implemented by classes
B. Only abstract classes can implement interfaces
C. No, a class can only implement one interface
D. Yes, a class can implement multiple interfaces
What is the purpose of an abstract class in Java?
A. To declare abstract methods
B. To provide a base class with common methods and fields
C. To make a class final
D. To declare abstract methods
yes