Signals a design smell indicating a class with insufficient responsibility, suggesting removal or merging.

Alerts developers to a potential design flaw that may indicate unnecessary complexity or missed abstraction.

When a class has few methods, little state, or merely delegates behavior to other classes.

During code reviews, refactoring sessions, or when reviewing object-oriented design for smells.

Detect a class with minimal behavior → consider merging it into a more cohesive class or removing it.

• Extract Class
• Collapse Hierarchy
• Refactor
• Code Smell detection tools
• Design Review

• Replace with a Data Class (holds data only) – may still be too thin
• Use a Utility Class (static methods) – shifts responsibility
• Merge into an existing Service class – consolidates behavior

Treating a lazy class as a separate entity → unnecessary indirection; Assuming delegation adds value → increased coupling; Removing the class without consolidating its behavior → loss of abstraction

God Class (excessive responsibilities) – opposite extreme; Data Class (holds data only) – similar thinness but intentional; Utility Class (static helpers) – not an object instance

Coming from Java: may create a lazy class to group static methods → in Python prefer a module; Coming from C++: might use inheritance to delegate behavior → can hide the laziness and increase complexity

• God Class
• Data Class
• Feature Envy
• Data Clumps
• Lazy Class

Do not introduce a lazy class when the class already has a clear, single responsibility; It has no measurable performance impact but adds indirection that can affect readability; Only consider it acceptable when it acts as a façade for a stable external API.

Eliminating lazy classes reduces codebase size, improves maintainability, and prevents unnecessary indirection.

A lazy class is like a middleman who never does any work themselves, just passes messages to others.

Lazy Class is part of the broader "Large Class" smell family and often co-occurs with Feature Envy.

Learn refactoring techniques such as Extract Class or Collapse Hierarchy to eliminate lazy classes.