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 A followed by b is an instance of
b is an instance of
b is an instance of
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(); }}

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

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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 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.
None of these
The code will lead to a compilation error as the display method is not declared as abstract.

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JAVA Interfaces and Abstract Classes
interface Base{ boolean m1 (); byte m2(short s);}which two code fragments will compile?1. interface Base2 implements Base {}2. abstract class Class2 extends Base { public boolean m1(){ return true; }}3. abstract class Class2 implements Base {}4. abstract class Class2 implements Base { public boolean m1(){ return (7 > 4); }}5. abstract class Class2 implements Base { protected boolean m1(){ return (5 > 7) }}

4 and 5
2 and 3
3 and 4
1 and 2
1 and 3

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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.
An abstract class can be used as a data type.
A subclass of a non-abstract superclass can be abstract.
All of these

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