What are the SOLID principles in Java OOP?

What are the SOLID principles in Java OOP?

The SOLID principles are a set of design principles that help developers create maintainable and scalable software. They include:

1. Single Responsibility Principle (SRP) - A class should have one, and only one, reason to change.
2. Open/Closed Principle (OCP) - Software entities should be open for extension but closed for modification.
3. Liskov Substitution Principle (LSP) - Objects of a superclass should be replaceable with objects of a subclass without affecting the correctness of the program.
4. Interface Segregation Principle (ISP) - No client should be forced to depend on methods it does not use.
5. Dependency Inversion Principle (DIP) - High-level modules should not depend on low-level modules; both should depend on abstractions.

Can you give an example of the Single Responsibility Principle?

Sure! Imagine a class called Report. If it handles both generating the report and sending it via email, it violates SRP. Instead, you could have one class ReportGenerator for creating the report and another class EmailSender for sending it. This way, each class has a single responsibility.

What about the Open/Closed Principle?

The Open/Closed Principle states that classes should be open for extension but closed for modification. For example, if you have a class Shape and you want to add new shapes like Circle or Square, you should be able to do this by extending the Shape class rather than modifying it directly.

How do these principles improve code quality?

These principles improve code quality by making it easier to understand, maintain, and extend. They promote better organization and reduce the risk of introducing bugs when changes are made.