- Duplicated Code
- Long Method
- Large Class
- Long Parameter List
- Divergent Change
- Shotgun Surgery
- Feature Envy
- Data Clumps
- Primitive Obsession
- Case Statements
- Parallel Inheritance Hierarchies
- Lazy Class
- Speculative Generality
- Temporary Field
- Message Chains
- Middle Man
- Inappropriate Intimacy
- Alternative Classes with Different Interfaces
- Incomplete Library Class
- Data Class
- Refused Bequest
- Comments
- Metaprogramming Madness
- Disjointed API
- Repetitive Boilerplate
Lazy Class
Each class you create costs money to maintain and understand. A class that isn't doing enough to pay for itself should be eliminated. Often this might be a class that used to pay its way but has been downsized with refactoring. Or it might be a class that was added because of changes that were planned but not made. Either way, you let the class die with dignity. If you have subclasses or modules that aren't doing enough, try to use Collapse Hierarchy. Nearly useless components should be subjected to Inline Class or Inline Module.