JAVA - INTERFACES AND PACKAGES MCQs

Which of these keywords is used to define packages in Java?

Which of this access specifies can be used for a class so that its members can be accessed by a different class in the same package?

Which of these access specifiers can be used for a class so that its members can be accessed by a different class in the different package?

Which of the following is the correct way of importing an entire package ‘pkg’?

Which of the following is an incorrect statement about packages?

Which of the following package stores all the standard java classes?

What is the output of this program?

Note : packages.class file is in directory pkg;

    package pkg;
    class display 
    {
        int x;
        void show() 
        {
            if (x > 1)
                System.out.print(x + " ");
        }
    }
    class packages 
    {
        public static void main(String args[]) 
        {
            display[] arr=new display[3];
            for(int i=0;i<3;i++)
                arr[i]=new display();
            arr[0].x = 0;      
            arr[1].x = 1;
            arr[2].x = 2;
            for (int i = 0; i < 3; ++i)
                arr[i].show();
         }
    }

What is the output of this program?

    package pkg;
    class output 
    {
        public static void main(String args[])
        { 
            StringBuffer s1 = new StringBuffer("Hello");
            s1.setCharAt(1, x);
            System.out.println(s1);
        }
    }

What is the output of this program?

Note : Output.class file is not in directory pkg.

   package pkg;
    class output 
    {
        public static void main(String args[])
        {
            StringBuffer s1 = new StringBuffer("Hello World");
            s1.insert(6 , "Good ");
            System.out.println(s1);
        }
   }

Which of these keywords is used to define interfaces in Java?

Which of these access specifiers can be used for an interface?

Which of these keywords is used by a class to use an interface defined previously?

Which of the following is the correct way of implementing an interface salary by class manager?

What is the output of this program

    interface calculate
    {
        void cal(int item);
    }
    class display implements calculate
    {
        int x;
        public void cal(int item)
        {
            x = item * item;            
        }
    }
    class interfaces
    {
        public static void main(String args[])
        {
            display arr = new display;
            arr.x = 0;      
            arr.cal(2);
            System.out.print(arr.x);
        }
    }

What is the output of this program

    interface calculate
    {
        void cal(int item);
    }
    class displayA implements calculate
    {
        int x;
        public void cal(int item)
        {
            x = item * item;            
        }
    }
    class displayB implements calculate
    {
        int x;
        public void cal(int item)
        {
            x = item / item;            
        }
    }
    class interfaces 
    {
        public static void main(String args[])
        {
            displayA arr1 = new displayA;
            displayB arr2 = new displayB;
            arr1.x = 0;
            arr2.x = 0;      
            arr1.cal(2);
            arr2.cal(2);
            System.out.print(arr1.x + " " + arr2.x);
        }
    

What is the output of this program?

interface calculate 
{
            int VAR = 0;
            void cal(int item);
}
        class display implements calculate 
        {
            int x;
          public  void cal(int item)
          {
                if (item<2)
                    x = VAR;
                else
                    x = item * item;            
            }
        }
 class interfaces 
{
 
            public static void main(String args[]) 
            {
                display[] arr=new display[3];
 
               for(int i=0;i<3;i++)
               arr[i]=new display();
               arr[0].cal(0);    
               arr[1].cal(1);
               arr[2].cal(2);
               System.out.print(arr[0].x+" " + arr[1].x + " " + arr[2].x);
            }
}

Which of the following access specifiers can be used for an interface?

Which of the following is the correct way of implementing an interface A by class B?

All methods must be implemented of an interface.

What type of variable can be defined in an interface?