Question

public class Exercise{

  public static void main(String [] arg){
    A b=new B();
    A c=new C();
    
    //B myB=new C();//must be a type error
    //The next assertion verifies that the former line would not typecheck
    assert !((Object)new C() instanceof B);
    
    //C myC=new B();//must be a type error
    //The next assertion verifies that the former line would not typecheck
    assert !((Object)new B() instanceof C);
  }
}
[???]
   

//what should I enter in place of the question marks to get this to work??

Answer 1

package com.HomeworkLib;

public class Exercise{

public static void main(String [] arg){
A b=new B();
A c=new C();
  
//B myB=new C();//must be a type error
//The next assertion verifies that the former line would not typecheck
assert !((Object)new C() instanceof B);
  
//C myC=new B();//must be a type error
//The next assertion verifies that the former line would not typecheck
assert !((Object)new B() instanceof C);
}
}

// Below section goes into ???
// Create interface A
interface A{
  
}
//Create Class B by implementing A
class B implements A{
  
}
//Create Class C by implementing A
class C implements A{
  
}

Output:

No compile time error.