Object Oriented Programming Foundations

Classes are templates to create objects, each with its own state, demonstrated by a Bike with attributes like color and speed, and operations start, stop, accelerate, printState.

Explore how encapsulation combines data and operations into a unit and hides data with private balance, using public debit, credit, and show balance methods to enforce constraints.

Explore what an object is by modeling a ShoppingCart with addToCart() and order(), using a linked list to store products, and see how each cart instance holds its own selections.

Explains method overloading with int, double, and string print methods and outlines rules such as changing at least one parameter and not overloading by return type.

Explore method overloading by implementing two search methods in a SearchUtil class: search(arr, ele) and search(arr, ele, start). These variants emphasize reuse and avoiding redundant code.

Understand static versus non-static members, where static members share a single class copy and non-static belong to each object. See how static utility methods and date formatting avoid object creation.

Explore how constructors initialize objects, overload to support no argument, one argument, and two argument options, and how the compiler may generate a default constructor.

Master the this keyword to access the current object from non-static member functions, resolve shadowing between local and instance variables, and delegate constructors with this(10).

Explore code reuse through inheritance by extending BasicCalc into ScientificCalc, inheriting add and subtract and adding sin, demonstrating is-a relationship and upcasting with BasicCalc references and Math.sin usage.

Demonstrates how overriding and dynamic binding work in a Base and Derived class, showing inherited and overridden methods and how calls resolve by object type.

Learn how Java handles inheritance and overriding, including why Java lacks multiple inheritance, the role of the Object base class, and using a vehicle hierarchy with covariant return types.

Explore abstract classes by defining a Graphic base with shared fields and methods, and use Line and Rectangle subclasses to override draw for specific shapes. Abstract methods enforce subclass implementations.

Explore how the final modifier enforces constants and prevents modification after initialization, especially for class-level constants like PI. It also prevents method overriding and class extension.

Understand abstract vs. concrete classes and how object creation uses reference variables. See how base classes can have partial implementations and require overriding abstract methods to form concrete subclasses.

Explore what an interface is and how MyCalc implements Calc by defining add, subtract, and sine. See how constants like pi and Calc references reveal interface behavior.

Explore implementing multiple interfaces in object-oriented programming by designing AudioPlayer and AudioRecorder, modeling multi-interface extensions, and understanding how a class extends one base class but implements several interfaces.

Learn how interfaces create loosely coupled code by decoupling client code from implementations through a video player interface, mp4/avi players, and a factory that selects the right player.

Explore how interfaces enable pluggable code by replacing inheritance with a Matcher interface and implementing match() for flexible algorithm use.