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 lead to a compilation error as declaration of the display method has been provided in two interface.
The code will compile and execute successfully showing the output Welcome to Examians.
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.
None of these

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JAVA Interfaces and Abstract Classes
In Java, declaring a class abstract is useful

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.

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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.
A subclass of a non-abstract superclass can be abstract.
A subclass can override a concrete method in a superclass to declare it abstract.
All of these
An abstract class can be extended.

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

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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();}}

will print Class One method
Compilation Error
None of these
will print Class Two method
compiles fine but print nothing

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JAVA Interfaces and Abstract Classes
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 occurs as the abstract class TestAbstract contains a non-abstract method.
None of these
Program compiles but leads to runtime exception.
Compilation error as class can not be declared as abstract.
Program will compile and execute successfully and prints

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