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 default implementations of some methods are not desirable. When it doesn't make sense to have objects of that class. 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 default implementations of some methods are not desirable. When it doesn't make sense to have objects of that class. ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes 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"); }} b is an instance of Nothing. b is an instance of b is an instance of A followed by b is an instance of b is an instance of Nothing. b is an instance of b is an instance of A followed by b is an instance of ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Runnable is a _____ . interface abstract class vaiable method class interface abstract class vaiable method class ANSWER DOWNLOAD EXAMIANS APP
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 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 Suppose A is an abstract class, B is a concrete subclass of A, and both A and B have a default constructor. Which of the following is correct?1. A a = new A();2. A a = new B();3. B b = new A();4. B b = new B(); 2 and 4 1 and 2 3 and 4 2 and 3 1 and 3 2 and 4 1 and 2 3 and 4 2 and 3 1 and 3 ANSWER DOWNLOAD EXAMIANS APP
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 3 and 6 3 and 5 1 and 2 5 and 6 2 and 4 3 and 6 3 and 5 1 and 2 5 and 6 ANSWER DOWNLOAD EXAMIANS APP
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