{"id":1284,"date":"2025-07-22T02:48:27","date_gmt":"2025-07-21T19:48:27","guid":{"rendered":"https:\/\/kienthucmo.com\/what-is-solid-principles-how-it-works-and-practical-applications\/"},"modified":"2025-12-07T12:07:31","modified_gmt":"2025-12-07T05:07:31","slug":"what-is-solid-principles-how-it-works-and-practical-applications","status":"publish","type":"post","link":"https:\/\/kienthucmo.com\/en\/what-is-solid-principles-how-it-works-and-practical-applications\/","title":{"rendered":"What is SOLID? Principles, how it works, and practical applications"},"content":{"rendered":"\n

During software development, every engineer aims to build products that not only run smoothly today but also remain flexible enough to evolve in the future. However, without proper design orientation from the very first lines of code, a system can easily fall into a trap of growing complexity, becoming difficult to extend and costly to maintain.<\/p>\n\n\n\n

That is why developers rely on well-established design principles that have been validated by the software engineering community over time. Among these guiding foundations, SOLID stands out as a core set of principles that helps shape a clear, extensible, and sustainably stable software architecture.<\/p>\n\n\n\n

1. What is SOLID?<\/h2>\n\n\n\n
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\"What<\/figure>\n<\/figure>\n\n\n\n

SOLID<\/strong> is an acronym for five software design principles:<\/p>\n\n\n\n

    \n
  • S \u2013 Single Responsibility Principle<\/strong> (Principle of Single Responsibility)<\/li>\n\n\n\n
  • O \u2013 Open\/Closed Principle<\/strong> (Open\/Closed Principle)<\/li>\n\n\n\n
  • L \u2013 Liskov Substitution Principle<\/strong> (Liskov Substitution Principle)<\/li>\n\n\n\n
  • I \u2013 Interface Segregation Principle<\/strong> (Interface Segregation Principle)<\/li>\n\n\n\n
  • D \u2013 Dependency Inversion Principle<\/strong> (Dependency Inversion Principle)
    <\/li>\n<\/ul>\n\n\n\n

    Introduced by Robert C. Martin<\/strong> (Uncle Bob) and popular in the Agile community, this set of principles was created to help software be maintainable, scalable, and testable<\/strong>, while reducing tight coupling between components<\/strong>.
    Whether you are programming in Java, C#, Python, or any other OOP language, SOLID remains a crucial foundation for building systems with a clear structure that can \u201cstay healthy\u201d for the long term.
    <\/p>\n\n\n\n

    2. How SOLID Principles Work<\/h2>\n\n\n\n

    Before diving into each principle, remember that SOLID is not a set of isolated rules, but a set of mutually supporting principles<\/strong>.
    Each principle addresses a specific aspect of software design, but when combined, they form a solid foundation that makes the code both readable and easy to extend and maintain.<\/p>\n\n\n\n

    Now, let’s explore these five principles one by one \u2013 starting with S<\/strong> and ending with D<\/strong> \u2013 to see how they work and the practical benefits they bring.
    <\/p>\n\n\n\n

    \"5<\/figure>\n\n\n\n

    2.1 Single Responsibility Principle (SRP) \u2013 Principle of Single Responsibility<\/h3>\n\n\n\n

    A class should have only one reason to change.<\/em><\/strong><\/p>\n\n\n\n

    Simply put: Each class should handle only one responsibility<\/strong>, and any changes to that class should come from only.
    <\/stronga>Example of SRP Violation:<\/strong><\/p>\n\n\n\n

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