Java is a pure object oriented programming language, why? Please explain in detail
Java is often described as a "pure" object-oriented programming (OOP) language, but this characterization can be somewhat nuanced. To understand why Java is considered pure in the context of OOP, we need to explore the principles of object-oriented programming and how Java adheres to them.
Encapsulation: This principle states that the internal state of an object should be hidden from the outside world. In Java, encapsulation is achieved through access modifiers (private, protected, public) and getter/setter methods.
Inheritance: This allows a new class to inherit properties and behaviors (methods) from an existing class. Java supports single inheritance (a class can inherit from one superclass) and multiple inheritance through interfaces.
Polymorphism: This allows methods to do different things based on the object that it is acting upon. In Java, polymorphism is achieved through method overloading (compile-time) and method overriding (runtime).
Abstraction: This principle involves hiding complex implementation details and showing only the essential features of an object. Java provides abstraction through abstract classes and interfaces.
Everything is an Object: In Java, almost everything is treated as an object. This includes user-defined classes, arrays, and even strings. The only exceptions are primitive data types (int, char, etc.), which are not objects. However, Java provides wrapper classes (like Integer, Character) that allow these primitives to be treated as objects when necessary.
Class-Based Structure: Java is a class-based language, meaning that all code is organized into classes. This enforces a structure where everything is encapsulated within classes, promoting the OOP paradigm.
No Global Functions: Unlike some other programming languages, Java does not allow global functions. All functions (methods) must belong to a class, reinforcing the idea that behavior is tied to objects.
Support for Interfaces: Java allows the creation of interfaces, which are contracts that classes can implement. This supports polymorphism and abstraction, allowing different classes to be treated as the same type if they implement the same interface.
Garbage Collection: Java has an automatic garbage collection mechanism that helps manage memory, which is an important aspect of object-oriented design. This allows developers to focus on the design and functionality of their objects without worrying about memory management.
While Java adheres closely to the principles of OOP, it is important to note that it is not "purely" object-oriented in the strictest sense due to the presence of primitive data types. However, the language provides a robust framework for object-oriented programming, and the use of wrapper classes helps mitigate this limitation.
Java is considered a pure object-oriented programming language because it emphasizes the core principles of OOP—encapsulation, inheritance, polymorphism, and abstraction—through its design and structure. While it does have some elements that are not strictly object-oriented (like primitive types), its overall architecture and approach to programming strongly align with the principles of OOP, making it a powerful tool for developers who want to leverage these concepts in their software design.