SOLID principles are a set of principles used to design software that is easy to maintain and extend over time. The principles are: Single Responsibility Principle (SRP) Open-Closed Principle (OCP) Liskov Substitution Principle (LSP) Interface Segregation Principle (ISP) Dependency Inversion Principle (DIP) Here are examples of each principle in Java and how they are interrelated: Single Responsibility Principle (SRP) The SRP states that a class should have only one reason to change.