JAVA Interfaces and Abstract Classes
Given the following piece of code:public interface Guard{ void doYourJob();}abstract public class Dog implements Guard{ }which of the following statements is correct?

This code will not compile, because in the declaration of class Dog we must use the keyword extends instead of implements.
This code will not compile, because class Dog must implement method doYourJob() from interface Guard.
This code will not compile, because method doYourJob() in interface Guard must be defined abstract.
This code will compile without any errors.

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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) }}

3 and 4
1 and 2
1 and 3
4 and 5
2 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 used as a data type.
A subclass can override a concrete method in a superclass to declare it abstract.
All of these
A subclass of a non-abstract superclass can be abstract.
An abstract class can be extended.

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

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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 will compile and execute successfully and prints
Program compiles but leads to runtime exception.
None of these
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
Given the following piece of code:public class School{ public abstract double numberOfStudent();}which of the following statements is true?

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

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