JAVA Interfaces and Abstract Classes In Java, declaring a class abstract is useful To force developers to extend the class not to use its capabilities. To prevent developers from further extending the class. When default implementations of some methods are not desirable. When it doesn't make sense to have objects of that class. When it makes sense to have objects of that class. To force developers to extend the class not to use its capabilities. To prevent developers from further extending the class. When default implementations of some methods are not desirable. When it doesn't make sense to have objects of that class. When it makes sense to have objects of that class. ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Which of the following statements regarding abstract classes are true? All of these A subclass can override a concrete method in a superclass to declare it abstract. A subclass of a non-abstract superclass can be abstract. An abstract class can be used as a data type. An abstract class can be extended. All of these A subclass can override a concrete method in a superclass to declare it abstract. A subclass of a non-abstract superclass can be abstract. An abstract class can be used as a data type. An abstract class can be extended. ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes What will be the output for the below code ?public interface TestInf{ int i =10;}public class Test{ public static void main(String... args){ TestInf.i=12; System.out.println(TestInf.i); }} Runtime Exception None of these Compile with error 12 10 Runtime Exception None of these Compile with error 12 10 ANSWER DOWNLOAD EXAMIANS APP
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? You must add a return statement in method numberOfStudent(). The keywords public and abstract cannot be used together. 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. The method numberOfStudent() in class School must have a body. Class School must be defined abstract. ANSWER DOWNLOAD EXAMIANS APP
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();}} Compilation Error None of these will print Class One method will print Class Two method compiles fine but print nothing Compilation Error None of these will print Class One method will print Class Two method compiles fine but print nothing 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(); 1 and 3 1 and 2 2 and 3 2 and 4 3 and 4 1 and 3 1 and 2 2 and 3 2 and 4 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
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