Inheritance

Notes on Inheritance (Full Set)

• Inherited state and methods are not repeated in subclass.
• Superclass may be complete class (can instantiate).
• Superclass may be abstract (incomplete; cannot instantiate).
• In subclass, invoke superclass constructor with super() "method".
• A redefined method (same signature, new body) overrides method from superclass; redefined method is executed instead.
• In redefined method, invoke overridden superclass method with super.method().
• Polymorphism means that may be used where objects of the superclass are expected.
• Dynamic binding means that the right method will be called.

---

• private: instance variables & methods cannot be accessed/used directly by the subclass
• public: can be accessed/used by subclass (or anyone)
• protected: accessible to class and its subclasses, but not to other classes (new keyword)