Superclass

Superclass is the parent class that a subclass (child) inherits from.
It defines common fields and methods that can be reused or overridden in subclasses.

class Animal { // superclass
    void speak() {
        System.out.println("Animal sound");
    }
}
 
class Dog extends Animal { // subclass
    void speak() {
        System.out.println("Bark");
    }
}

Key Terms

Term	Meaning
Superclass	The base or parent class
Subclass	The class that extends it
super	Keyword to refer to superclass

Accessing Superclass Members

class Animal { // superclass
    void speak() {
        System.out.println("Animal sound");
    }
}
 
class Cat extends Animal { // subclass
    void speak() {
        super.speak(); // Calls Animal's speak()
        System.out.println("Meow");
    }
}

Key Points

• Subclass inherits all non-private members of the superclass.
• Use super.method() to call the superclass version.
• Use super() to call the superclass constructor.
• A class can have only one direct superclass (Java supports single inheritance).

Real-World Analogy

If car is a class, then Vehicle might be its superclass - every car is a vehicle, so shares common traits.

Tip

Be ready to explain:

• the difference between class extension vs interface implementation,
• when to use super() vs this(),
• why Java only supports single class inheritance.

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Parent: _OOP