SOLID is a set of five object-oriented design principles — Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, and Dependency Inversion — that guide the structuring of classes and their relationships to produce code that is cohesive, extensible, and loosely coupled. Each principle addresses a distinct axis of class design: how responsibilities are distributed within a class, how new behavior is added without altering existing code, how subtypes must remain behaviorally consistent with their supertypes, how interfaces should be scoped to the needs of their clients, and how high-level modules should depend on abstractions rather than concrete implementations. Together these principles belong to the domain of object-oriented software design and inform how classes, interfaces, and inheritance/composition hierarchies are structured within a broader software engineering discipline.
SOLID is a set of five object-oriented design principles — Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, and Dependency Inversion — that guide the structuring of cla…