The super keyword

The super keyword refers to the immediate superclass. It is used for two purposes:

1. Access superclass fields and methods

When a subclass overrides a method or hides a field, super can be used to access the superclass version.

class Parent {
    String name = "Parent";
    void show() {
        System.out.println("Parent show");
    }
}

class Child extends Parent {
    String name = "Child";
    void show() {
        super.show();                 // call parent method
        System.out.println(super.name); // access parent field
        System.out.println(this.name);   // child field
    }
}

2. Call superclass constructor

The super() call must be the first statement in a constructor. It invokes the parent class constructor.

class Parent {
    Parent(String message) {
        System.out.println("Parent: " + message);
    }
}

class Child extends Parent {
    Child(String msg) {
        super(msg);   // must be first
        System.out.println("Child constructor");
    }
}

Important: If a constructor does not explicitly call super() or this(), the compiler inserts super() (calling the no‑argument constructor of the parent). If the parent lacks a no‑argument constructor, you must explicitly call a parameterized super().

class Parent {
    Parent(int x) { }
}
class Child extends Parent {
    Child() {
        super(10); // required
    }
}