SOLID Design Principles - Identifying From Code

Single Responsibility Principle

Look for classes with methods addressing different concerns

Open/Closed Principle

Identify code that requires modifying existing method implementations to add new functionality instead of extending through inheritance or composition.

Liskov Substitution Principle

Watch for subclasses that override methods in ways that change expected behavior, throw unexpected exceptions, or break contracts established by the parent class.

Interface Segregation Principle

Spot large interfaces with methods that aren't all used by each implementing class, forcing classes to implement methods they don't need.

Dependency Inversion Principle

Look for high-level modules directly instantiating or depending on concrete low-level modules rather than depending on abstractions/interfaces.

Law of Demeter

Notice method chains accessing distant objects (like object.getX().getY().getZ()) rather than talking only to immediate collaborators.