Question

Java Question:

Which of the following statements about the reference super is true?

	a) It must be used every time a method from the superclass is called.
	b) It must be the last statement of the subclass constructor.
	c) It must be the first statement of the subclass constructor.
	d) It can only be used once in a program.

Answer 1

Only option C is correct

a) We do not need to explicity add super before the method invocation of the parent class. It is done automatically by the JVM. So, even if we do not write super.methodCall(), it will still work

Ex:

class A{
        public void test() {
     System.out.print("A");             
        }
}


class B extends A{
        public void test2() {
                test(); // super.test(); ----> Same thing
        }
        
        public static void main(String[] args) {
                B b = new B();
                b.test2();
        }
}

b)
It has to be the first statement, not the last. As, whenever object of child class is created, the constructor of parent class should run first before any code runs for child class.
Though we do not have to define super() explicitly, JVM does it for us, but in the actual code, it has to be the first statement.

Ex:


- If we try to add at last, we get this error



c) As explained above, it has to be the first statement. THIS IS RIGHT

d) We can use super at multiple places like -
- calling functions of parent class (Though Implicit)
- calling constructor of parent class.
- referring to variable of parent class


ONLY part C is right and I have explained why others are wrong


Kindly upvote if this helped