abstract classes

Multiple Choice Question

QID: 
48

Given:

interface I {
}

class A implements I {
	
	public void m(){
		
	}
}

abstract class B extends A { //line 1

	public abstract void m(); //line 2
}

class C extends B { //line 3
	
}

 

Select 1 option

A. Class will compile successfully

B. Compilation will fail at line marked as line 1.

C. Compilation will fail at line marked as line 2.

D. Compilation will fail at line marked as line 3.

Multiple Choice Question

QID: 
45

Given interface Inter

interface Inter {
	
	void myMethod();
}

Which all implementations are valid?

A.

abstract class MyAbstract implements Inter{

    public abstract void myMethod();
}

B.

abstract class MyAbstract1 implements Inter{

    abstract void myMethod();
}

C.

abstract class MyAbstract2 implements Inter{

    void myMethod();
}

D.

abstract class MyAbstract3 implements Inter{

    void myMethod() {}
}

E.

abstract class MyAbstract4 implements Inter{

    public void myMethod() {}
}

F.

abstract class MyAbstract5 implements Inter{

    public abstract void myMethod() {}
}

G.

abstract class MyAbstract implements Inter{

    @Override
    public abstract void myMethod();
}

 

Multiple Choice Question

QID: 
3

Given:

abstract class Abstract1 {

  public abstract static void main(String[] args);

}

abstract class Concrete1 extends Abstract1{

  public static void main(String[] args) {

   System.out.println("I am an abstrsct class"); 

}

}

What will be the result is we compile and run Concrete1?

Select 1 option:

A. Class Abstract1 will not compile

B. Classes will compile, but will fail at runtime as Concrete1 is an abstract class

C. Class will compile, run and print "I am an abstract class"

D. Class will compile, run and print nothing

Multiple Choice Question

QID: 
2

Given:

abstract class Abstract1 {

  public static void main(String[] args) {

   System.out.println("I am an abstrsct class");
  }
}

abstract class Concrete1 extends Abstract1{
}

What will be the result is we compile and run Concrete1?

Select 1 option:

A. Class Abstract1 will not compile as abstract classes cannot have main method

B. Classes will compile, but will fail at runtime as Concrete1 does not have a main method

C. Class will compile, run and print "I am an abstract class"

D. Class will compile, run and print nothing

 

Multiple Choice Question

QID: 
1

Given:

public abstract class Abstract1 {

  public static void main(String[] args) {

    System.out.println("I am an abstract class");

  }

}

Select 1 option:

A. Class will not compile as abstract classes cannot have main method

B. Class will compile, but will not execute as we cannot execute an abstract class main method

C. Class will compile, run and print "I am an abstract class"

D. Class will compile, run and print nothing

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