在继承方面，super和this有什么区别？

Question

Here is my question, super keyword is used only in case of inheritence ? In terms of inheritence, what is the difference between this and super ?

Answer 1

• this refers to the current object , ie it's a reference
• super refers to the super class , ie it's a scoping mechanism

The current object is the same object as the object of the superclass. If you have a Dog that extends Animal , and do new Dog() then you create 1 object, and this object is both the Animal instance and the Dog instance.

Here's an example

class Dog extends Animal {

    public void treatWell(DogSpa spa) {
        spa.takeCareOf(this);      // pass this object to the spa
    }

    public void makeSound() {
        System.out.println("bark");
        super.makeSound();         // call makeSound in Animal scope
    }
}

Answer 2

this refers to current object, while super refers to current object's parent class.

Consider this:

class Parent {
    protected int value;
    public void test() {
         //print parent
    }
}

class Child extends Parent {
    public void test() {
       //print child
    }
    private void someMethod() {
        this.test();//will print child
        super.test();//will print parent
    }        
}