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().
Class School must be defined abstract.
The keywords public and abstract cannot be used together.
The method numberOfStudent() in class School must have a body.

ANSWER DOWNLOAD EXAMIANS APP

JAVA Interfaces and Abstract Classes
What will happen after compiling this program code?abstract class MyClass{ //line 1 private int a, b; public void call(int a, int b){ this.a = a; this.b = b; System.out.print(a+b); }}public class Test{ public static void main(String args[]){ MyClass m = new MyClass(); //line 2 m.call(12,25); }}

Compilation error due to line 2
Successful run and print 37
Compilation error due to line 1
None of these
Runtime error

ANSWER DOWNLOAD EXAMIANS APP

JAVA Interfaces and Abstract Classes
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(); }}

The code will compile and execute successfully showing the output Welcome to Examians.
The code will lead to a compilation error as declaration of the display method has been provided in two interface.
None of these
The code will lead to a compilation error as the display method is not declared as abstract.
The code will lead to a compilation error due to public modifier while declaring the display method.

ANSWER DOWNLOAD EXAMIANS APP

JAVA Interfaces and Abstract Classes
Which of the following statements regarding abstract classes are true?

An abstract class can be extended.
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.
All of these

ANSWER DOWNLOAD EXAMIANS APP