Which of the following class definitions defines a legal abstract class? abstract class A { abstract void unfinished(); } public class abstract A { abstract void unfinished(); } class A { abstract void unfinished(); } class A { abstract void unfinished() { } } TRUE ANSWER : ? YOUR ANSWER : ?
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(); 3 and 4 1 and 2 2 and 3 2 and 4 1 and 3 TRUE ANSWER : ? YOUR ANSWER : ?
Which of the following statements regarding abstract classes are true? A subclass can override a concrete method in a superclass to declare it abstract. All of these An abstract class can be used as a data type. A subclass of a non-abstract superclass can be abstract. An abstract class can be extended. TRUE ANSWER : ? YOUR ANSWER : ?
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(); }} None of these The code will lead to a compilation error as the display method is not declared as abstract. The code will compile and execute successfully showing the output Welcome to Examians. The code will lead to a compilation error due to public modifier while declaring the display method. The code will lead to a compilation error as declaration of the display method has been provided in two interface. TRUE ANSWER : ? YOUR ANSWER : ?
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? 2 3 4 None of these 1 TRUE ANSWER : ? YOUR ANSWER : ?
What will be the output when the following program is compiled and executed?abstract class TestAbstract{ String my_name; String myName(){ my_name = "Examveda"; return my_name; } abstract void display();}public class Test extends TestAbstract{ void display(){ String n = myName(); System.out.print("My name is "+ n); } public static void main(String args[]){ Test t = new Test(); t.display(); }} Compilation error as class can not be declared as abstract. Compilation error occurs as the abstract class TestAbstract contains a non-abstract method. None of these Program will compile and execute successfully and prints Program compiles but leads to runtime exception. TRUE ANSWER : ? YOUR ANSWER : ?
Which of the following declares an abstract method in an abstract Java class? public abstract void method(); public abstract method(); public void method() {} public abstract void method() {} public void abstract Method(); TRUE ANSWER : ? YOUR ANSWER : ?
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. You must add a return statement in method numberOfStudent(). The keywords public and abstract cannot be used together. TRUE ANSWER : ? YOUR ANSWER : ?
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()); }} None of these Compilation fails due to an error on lines 1 test-name Compilation fails due to an error on lines 2 Compilation succeed but Runtime Exception TRUE ANSWER : ? YOUR ANSWER : ?