Object-Oriented Programming in Java

Study Notes

Class: A blueprint or template that defines the properties and behavior of an object.
Object: An instance of a class, with its own set of attributes (data) and methods (functions).
Inheritance: A mechanism that allows one class to inherit the properties and behavior of another class.
Polymorphism: The ability of an object to take on multiple forms, depending on the context.
Abstraction: The concept of showing only the necessary information to the outside world, while hiding the implementation details.
Encapsulation: The practice of bundling data and methods that operate on that data within a single unit (class).

Single Responsibility Principle (SRP): A class should have only one reason to change.
Open/Closed Principle: A class should be open for extension but closed for modification.
Liskov Substitution Principle: Subtypes should be substitutable for their base types.
Interface Segregation Principle: A client should not be forced to depend on interfaces it does not use.
Dependency Inversion Principle: High-level modules should not depend on low-level modules, but both should depend on abstractions.

Abstract Classes: Classes that cannot be instantiated and are used as base classes for other classes.
Interfaces: Abstract classes that define a contract or a set of methods that must be implemented.
Overloading: Defining multiple methods with the same name but different parameters.
Overriding: Providing a specific implementation of a method that is already defined in a superclass.
Method Hiding: Defining a static method with the same name as an instance method in a superclass.

Modularity: Breaking down a program into smaller, independent modules that can be easily maintained and updated.
Reusability: Writing code that can be reused in multiple contexts.
Easier Maintenance: Organizing code in a way that makes it easier to understand and modify.
Improved Code Quality: Encouraging good programming practices, such as encapsulation and abstraction.

A class is a blueprint or template that defines the properties and behavior of an object.
An object is an instance of a class, with its own set of attributes (data) and methods (functions).
Inheritance is a mechanism that allows one class to inherit the properties and behavior of another class.
Polymorphism is the ability of an object to take on multiple forms, depending on the context.
Abstraction is the concept of showing only the necessary information to the outside world, while hiding the implementation details.
Encapsulation is the practice of bundling data and methods that operate on that data within a single unit (class).

High-level modules should not depend on low-level modules, but both should depend on abstractions.

Abstract classes are classes that cannot be instantiated and are used as base classes for other classes.
Interfaces are abstract classes that define a contract or a set of methods that must be implemented.
Method overloading is defining multiple methods with the same name but different parameters.
Method overriding is providing a specific implementation of a method that is already defined in a superclass.
Method hiding is defining a static method with the same name as an instance method in a superclass.

Modularity breaks down a program into smaller, independent modules that can be easily maintained and updated.
Reusability allows writing code that can be reused in multiple contexts.
Easier maintenance organizes code in a way that makes it easier to understand and modify.
Improved code quality encourages good programming practices, such as encapsulation and abstraction.