OBJECT-ORIENTED PROGRAMMING PRINCIPLES AND THEIR IMPACT ON MODERN SOFTWARE DESIGN

Object-oriented programming (OOP) has remained one of the dominant paradigms in software engineering since its emergence in the 1960s. This paper reviews the literature on the four core OOP principles - encapsulation, inheritance, polymorphism, and abstraction - and examines their influence on modern software design. It traces the evolution of these principles from early object-oriented research to contemporary practices such as SOLID principles, design patterns, and hybrid object-oriented/functional approaches. The review also discusses key challenges, particularly the tension between inheritance and encapsulation, and analyzes how modern languages including Kotlin, Swift, Rust, and Scala address these issues through traits, pattern matching, and immutability. The findings indicate that although OOP has evolved significantly, its fundamental principles remain central to developing maintainable, reusable, and scalable software systems. Rather than replacing OOP, modern language features refine and extend its core concepts to meet contemporary software engineering requirements.