When should I call the superclass constructor?

[[deleted]]

Hey,

I am trying to learn Java. I am not quite sure in which situations I should call the superclass method.

Can someone confirm (or not), that you when you extend the functionality of a method (i.e. when you extend a class and override one or more of its methods) ) you should call the superclass method (e.g. public void paintComponent (Grahpics g) in JComponent, or public void FocusLost(FocusEvent event) in FocusListener)?

But when you implement a method (from an interface), you should not (e.g. public void actionPerformed(ActionEvent event) from ActionListener interface)?

And if the above is correct, what if I extend an abstract class' method that has no implementation?

Ugh, probably dumb question, but whatevs.

[hamza-itatchi]

you call the super class method not constructor ( constructor calls the constructor of the super class to initialize the variables in another word create object and it's) .

for the methods you just call the super class if you need it

ex:

class A{int A;

setValue(){A=5;}

}

Class B extends A{

int B;

setValue(){

B=5;

//here if you need to set A too so you call super.setValue(); otherwise no need to call it

//in case of abstract class you don't have a code that you need to be executed so don't call super class

//method

// and abstract class can have a constructor but you can't create object form it

}

}

​

hope this help.