JAVA Interfaces and Abstract Classes interface Test{ int p = 10; //line 1 public int q = 20; //line 2 public static int r = 30; //line 3 public static final int s = 40; //line 4}Which of the above line will give compilation error? 4 None of these 3 1 2 4 None of these 3 1 2 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? The method numberOfStudent() in class School must have a body. 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. Class School must be defined abstract. The keywords public and abstract cannot be used together. You must add a return statement in method numberOfStudent(). 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 A followed by b is an instance of b is an instance of b is an instance of Nothing. b is an instance of A followed by b is an instance of b is an instance of ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Which of the following statements regarding abstract classes are true? An abstract class can be used as a data type. All of these An abstract class can be extended. A subclass of a non-abstract superclass can be abstract. A subclass can override a concrete method in a superclass to declare it abstract. An abstract class can be used as a data type. All of these An abstract class can be extended. A subclass of a non-abstract superclass can be abstract. A subclass can override a concrete method in a superclass to declare it abstract. ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes In Java, declaring a class abstract is useful When it makes sense to have objects of that class. To force developers to extend the class not to use its capabilities. When it doesn't make sense to have objects of that class. 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. To force developers to extend the class not to use its capabilities. When it doesn't make sense to have objects of that class. When default implementations of some methods are not desirable. To prevent developers from further extending the class. ANSWER DOWNLOAD EXAMIANS APP
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()); }} test-name Compilation fails due to an error on lines 1 Compilation succeed but Runtime Exception Compilation fails due to an error on lines 2 None of these test-name Compilation fails due to an error on lines 1 Compilation succeed but Runtime Exception Compilation fails due to an error on lines 2 None of these ANSWER DOWNLOAD EXAMIANS APP
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