Inheritance & Abstract Classes in Java
From the Java cheat sheet · Inheritance & Interfaces · verified Jul 2026
Inheritance & Abstract Classes
extends, super, overriding, and abstract base classes.
java
// Quick Reference
class Dog extends Animal {
@Override
void speak() { System.out.println("Woof"); }
}
abstract class Animal { abstract void speak(); }💡 super(...) calls the parent constructor and must be the first statement.
⚡ @Override is optional but lets the compiler catch signature mistakes.
📌 Abstract classes can mix abstract and concrete methods and hold state.
🟢 Polymorphism: a parent-typed reference dispatches to the actual subclass method.
inheritanceabstract