- 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
Shotgun Surgery
Shotgun surgery is similar to divergent change but is the opposite. You whiff this when every time you make a kind of change, you have to make a lot of little changes to a lot of different classes. When the changes are all over the place, they are hard to find, and it's easy to miss an important change.
In this case you want to use Move Method and Move Field to put all the changes into a single class. If no current class looks like a good candidate, create one. Often you can use Inline Class to bring a whole bunch of behavior together. You get a small dose of divergent change, but you can easily deal with that.
Divergent change is one class that suffers many kinds of changes, and shotgun surgery is one change that alters many classes. Either way you want to arrange things so that, ideally, there is a one-to-one link between common changes and classes.