What is SOLID principle?? SOLID principles are the design principles that enable us manage most of the software design problem. The terms SOLID is an acronym for five design principles intended to make software designs more understandable , flexible and maintainable The principles are subset of many principles promoted by Robert C . Martin. Why we use SOLID principles in our program?? To achieve reduction in complexity of code. To increase readability, extensibility and maintenance. To reduce error and implement reusability. To achieve better testability. To reduce tight coupling. SOLID acronym S : Single responsibility principle O :Open closed principle L :Liskov substitution principle I :Interface segregation principle D :Dependency inversion principle Single responsibility principle. “A class ...